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Sample records for fiber taper extraction

  1. Coupled fiber taper extraction of 1.53 microm photoluminescence from erbium doped silicon nitride photonic crystal cavities.

    PubMed

    Shambat, Gary; Gong, Yiyang; Lu, Jesse; Yerci, Selçuk; Li, Rui; Dal Negro, Luca; Vucković, Jelena

    2010-03-15

    Optical fiber tapers are used to collect photoluminescence emission at approximately 1.5 microm from photonic crystal cavities fabricated in erbium doped silicon nitride on silicon. In the experiment, photoluminescence collection via one arm of the fiber taper is enhanced 2.5 times relative to free space collection, corresponding to a net collection efficiency of 4%. Theoretically, the collection efficiency into one arm of the fiber-taper with this material system and cavity design can be as high as 12.5%, but the degradation of the experimental coupling efficiency relative to this value mainly comes from scattering loss within the short taper transition regions. By varying the fiber taper offset from the cavity, a broad tuning range of coupling strength and collection efficiency is obtained. This material system combined with fiber taper collection is promising for building on-chip optical amplifiers.

  2. Pump and Signal Taper for Airclad Fibers

    DTIC Science & Technology

    2006-01-05

    as follows: Crystal Fibre A/S will develop a taper/coupler solution to interface between a new polarization maintaining/polarizing amplifier fiber ...MM) pump combiner with a high NA air-clad output. The input side of the combiner is 7 individual MM pump delivery solid all- glass fibers . The NA of...pump combiner. MOTIVATION FINAL REPORT ITEM 0002 In a typical standard fused fiber coupler a number of all- glass 0.22 NA pump

  3. Fiber taper coupling to chalcogenide microsphere modes

    SciTech Connect

    Grillet, Christian; Bian Shuning; Magi, Eric C.; Eggleton, Benjamin J.

    2008-04-28

    We report the fabrication and optical characterization of microsphere in chalcogenide (As{sub 2}Se{sub 3}). We show that high Q modes of a 9.2 {mu}m diameter chalcogenide glass can be efficiently excited via evanescent coupling using a silica tapered fiber. Loaded Q factors of more than 20 000 have been measured. Fine analysis of the coupling spectrum around 1619 nm led to an estimation of the microsphere eccentricity of less than 1%. Owing to the unique combination properties of chalcogenide glass and the microspheres geometry, we expect this architecture to offer an ideal environment for versatile applications on both the telecommunication and midinfrared wavelength windows.

  4. Polarization-independent all-fiber isolator based on asymmetric fiber tapers.

    PubMed

    Fang, X

    1996-11-01

    Nonreciprocal intensity transmission in optical fibers can be realized by use of an asymmetric fiber taper. A few-mode fiber taper-based nonreciprocal component is designed, and its nonreciprocal transmission characteristics are demonstrated. This structure can be employed to build polarization-independent all-fiber isolators or fiber-optic sensors.

  5. Nonlinear transmission through a tapered fiber in rubidium vapor

    SciTech Connect

    Hendrickson, S. M.; Pittman, T. B.; Franson, J. D.

    2009-02-15

    Subwavelength-diameter tapered optical fibers surrounded by rubidium vapor can undergo a substantial decrease in transmission at high atomic densities due to the accumulation of rubidium atoms on the surface of the fiber. Here we demonstrate the ability to control these changes in transmission using light guided within the taper. We observe transmission through a tapered fiber that is a nonlinear function of the incident power. This effect can also allow a strong control beam to change the transmission of a weak probe beam.

  6. Compact fiber optic immunosensor using tapered fibers and acoustic enhancement

    NASA Astrophysics Data System (ADS)

    Zhou, Chonghua; Pivarnik, Philip E.; Auger, Steven; Rand, Arthur G.; Letcher, Stephen V.

    1997-06-01

    A compact fiber-optic sensing system that features all-fiber optical design and semiconductor-laser excitation has been developed and tested. A 2X2 fiber coupler directs the input light to the SMA connected sensing fiber tip and the fluorescent signal back to a CCD fiber spectrophotometer. In this system, the fluorescent signal is confined in the fiber system so the signal-to-noise ratio is greatly improved and the system can be operate in ambient light conditions. The utilization of a red laser diode has reduced the background signal of non-essential biomolecules. The fluorescent dye used is Cy5, which has an excitation wavelength of 650 nm and a fluorescent center wavelength of 680 nm. To illustrate the biosensor's diagnostic capabilities, a sandwich immunoassay to detect Salmonella is presented. Tapered fiber tips with different shapes and treatments were studied and optimized. An enhancement system employing ultrasonic concentration of target particles has also been developed and applied to the detection of Salmonella. The immunoassay was conducted in a test chamber that also serves as an ultrasonic standing-wave cell and allows microspheres to be concentrated in a column along the fiber probe. The system demonstrates broad promise in future biomedical application.

  7. Tapered fiber bundles for combining high-power diode lasers.

    PubMed

    Kosterin, Andrey; Temyanko, Valery; Fallahi, Mahmoud; Mansuripur, Masud

    2004-07-01

    Tapered fiber bundles are often used to combine the output power of several semiconductor lasers into a multimode optical fiber for the purpose of pumping fiber lasers and amplifiers. It is generally recognized that the brightness of such combiners does not exceed the brightness of the individual input fibers. We report that the brightness of the tapered fibers (and fiber bundles) depends on both the taper ratio and the mode-filling properties of the beams launched into the individual fibers. Brightness, therefore, can be increased by selection of sources that fill a small fraction of the input fiber's modal capacity. As proof of concept, we present the results of measurements on tapered fiber-bundle combiners having a low-output étendue. Under low mode-filling conditions per input multimode fiber (i.e., fraction of filled modes < or =0.29), we report brightness enhancements of 8.0 dB for 19 x 1 bundles, 6.7 dB for 7 x 1 bundles, and 4.0 dB for 3 x 1 combiners. Our measured coupling efficiency variations of approximately 1%-2% among the various fibers in a given bundle confirm the uniformity and quality of the fabricated devices.

  8. Tapered fluorotellurite microstructured fibers for broadband supercontinuum generation.

    PubMed

    Wang, Fang; Wang, Kangkang; Yao, Chuanfei; Jia, Zhixu; Wang, Shunbin; Wu, Changfeng; Qin, Guanshi; Ohishi, Yasutake; Qin, Weiping

    2016-02-01

    Fluorotellurite microstructured fibers (MFs) based on TeO2-BaF2-Y2O3 glasses are fabricated by using a rod-in-tube method. Tapered fluorotellurite MFs with varied transition region lengths are prepared by employing an elongation machine. By using a tapered fluorotellurite MF with a transition region length of ∼3.3  cm as the nonlinear medium and a 1560 nm femtosecond fiber laser as the pump source, broadband supercontinuum generation covering from 470 to 2770 nm is obtained. The effects of the transition region length of the tapered fluorotellurite MF on supercontinuum generation are also investigated. Our results show that tapered fluorotellurite MFs are promising nonlinear media for generating broadband supercontinuum light expanding from visible to mid-infrared spectral region.

  9. Pulse Compression using a Tapered Microstructure Optical Fiber

    DTIC Science & Technology

    2006-04-01

    Pulse compression using a tapered microstructure optical fiber Jonathan Hu, Brian S. Marks, and Curtis R. Menyuk University of Maryland Baltimore...R. Menyuk , ”Optimization of the Split-Step Fourier Method in Modeling Optical-Fiber Communications Systems,” J. Lightwave Technol. 21, 61–68 (2003

  10. Single muscle fiber gene expression with run taper.

    PubMed

    Murach, Kevin; Raue, Ulrika; Wilkerson, Brittany; Minchev, Kiril; Jemiolo, Bozena; Bagley, James; Luden, Nicholas; Trappe, Scott

    2014-01-01

    This study evaluated gene expression changes in gastrocnemius slow-twitch myosin heavy chain I (MHC I) and fast-twitch (MHC IIa) muscle fibers of collegiate cross-country runners (n = 6, 20±1 y, VO₂max = 70±1 ml•kg-1•min-1) during two distinct training phases. In a controlled environment, runners performed identical 8 kilometer runs (30:18±0:30 min:s, 89±1% HRmax) while in heavy training (∼72 km/wk) and following a 3 wk taper. Training volume during the taper leading into peak competition was reduced ∼50% which resulted in improved race times and greater cross-section and improved function of MHC IIa fibers. Single muscle fibers were isolated from pre and 4 hour post run biopsies in heavily trained and tapered states to examine the dynamic acute exercise response of the growth-related genes Fibroblast growth factor-inducible 14 (FN14), Myostatin (MSTN), Heat shock protein 72 (HSP72), Muscle ring-finger protein-1 (MURF1), Myogenic factor 6 (MRF4), and Insulin-like growth factor 1 (IGF1) via qPCR. FN14 increased 4.3-fold in MHC IIa fibers with exercise in the tapered state (P<0.05). MSTN was suppressed with exercise in both fiber types and training states (P<0.05) while MURF1 and HSP72 responded to running in MHC IIa and I fibers, respectively, regardless of training state (P<0.05). Robust induction of FN14 (previously shown to strongly correlate with hypertrophy) and greater overall transcriptional flexibility with exercise in the tapered state provides an initial molecular basis for fast-twitch muscle fiber performance gains previously observed after taper in competitive endurance athletes.

  11. Tapered rib fiber coupler for semiconductor optical devices

    DOEpatents

    Vawter, Gregory A.; Smith, Robert Edward

    2001-01-01

    A monolithic tapered rib waveguide for transformation of the spot size of light between a semiconductor optical device and an optical fiber or from the fiber into the optical device. The tapered rib waveguide is integrated into the guiding rib atop a cutoff mesa type semiconductor device such as an expanded mode optical modulator or and expanded mode laser. The tapered rib acts to force the guided light down into the mesa structure of the semiconductor optical device instead of being bound to the interface between the bottom of the guiding rib and the top of the cutoff mesa. The single mode light leaving or entering the output face of the mesa structure then can couple to the optical fiber at coupling losses of 1.0 dB or less.

  12. Confinement loss in adiabatic photonic crystal fiber tapers

    NASA Astrophysics Data System (ADS)

    Kuhlmey, Boris T.; Nguyen, Hong C.; Steel, M. J.; Eggleton, Benjamin J.

    2006-09-01

    We numerically study confinement loss in photonic crystal fiber (PCF) tapers and compare our results with previously published experimental data. Agreement between theory and experiment requires taking into account hole shrinkage during the tapering process, which we measure by using a noninvasive technique. We show that losses are fully explained within the adiabatic approximation and that they are closely linked to the existence of a fundamental core-mode cutoff. This cutoff is equivalent to the core-mode cutoff in depressed-cladding fibers, so that losses in PCF tapers can be obtained semiquantitatively from an equivalent depressed-cladding fiber model. Finally, we discuss the definition of adiabaticity in this open boundary problem.

  13. Perfluorinated plastic optical fiber tapers for evanescent wave sensing.

    PubMed

    Gravina, Roberto; Testa, Genni; Bernini, Romeo

    2009-01-01

    In this work we describe the fabrication and the characterization of perfluorinated plastic-cladded optical fiber tapers. The heat-and-pull procedure has been used to fabricate symmetric tapers. Devices with different taper ratio have been produced and the repeatability of the process has been verified. The very low refractive indexes of the core-cladding perfluorinated polymers (n = 1.35-1.34) permit a strong enhancement of the evanescent wave power fraction in aqueous environments (n = 1.33), making them very attractive for evanescent wave sensing. The tapers have been characterized carrying out evanescent field absorbance measurements with different concentrations of methylene blue in water and fluorescence collection measurements in an aqueous solution containing Cy5 dye. A good sensitivity, tightly related to the low refractive index of the core-cladding materials and the geometrical profile, has been shown.

  14. Refractive index sensor based on tapered multicore fiber

    NASA Astrophysics Data System (ADS)

    Zhang, Chuanbiao; Ning, Tigang; Li, Jing; Pei, Li; Li, Chao; Lin, Heng

    2017-01-01

    A novel refractive index (RI) sensor based on middle-tapered multicore fiber (TMCF) is proposed and experimentally demonstrated. The sensing structure consists of two singlemode fibers (SMF) and simply spliced a section tapered four-core fiber between them. The light injected from the SMF into the multicore fiber (MCF) will excite multiple cladding mode, and interference between these modes can be affected by the surrounding refractive index (SRI), which also dictates the wavelength shift of the transmission spectrum. Our experimental investigations achieved a sensitivity around 171.2 nm/RIU for a refractive index range from 1.3448 to 1.3774. All sensors fabricated in this paper show good linearity in terms of the spectral wavelength shift versus changes in RI.

  15. Fast profile measurement of micrometer-sized tapered fibers with better than 50-nm accuracy

    NASA Astrophysics Data System (ADS)

    Warken, Florian; Giessen, Harald

    2004-08-01

    The forward scattering of light illuminating a transparent dielectric cylinder, such as a tapered fiber, from the side can be understood as interference of the diffracted, reflected, and transmitted light. Additionally, light can be resonantly coupled into the fiber if a multiple of the wavelength matches the circumference. Using a suitable laser setup with a novel evaluation algorithm allows us to quickly extract the fiber radius from the complex diffraction pattern, obtaining an accuracy of better than 50 nm. We demonstrate experimentally our method, which is noncontact and allows one to simultaneously measure the profile of a several-centimeter-long fiber waist with a diameter near the diffraction limit.

  16. Fiber Volume Fraction Influence on Fiber Compaction in Tapered Resin Injection Pultrusion Manufacturing

    NASA Astrophysics Data System (ADS)

    Masuram, N. B.; Roux, J. A.; Jeswani, A. L.

    2016-06-01

    Liquid resin is injected into the tapered injection chamber through the injection slots to completely wetout the fiber reinforcements in a resin injection pultrusion process. As the resin penetrates through the fibers, the resin also pushes the fibers away from the wall towards the centerline causing compaction of the fiber reinforcements. The fibers are squeezed together due to compaction, making resin penetration more difficult; thus higher resin injection pressures are required to effectively penetrate through the fibers and achieve complete wetout. Fiber volume fraction in the final pultruded composite is a key to decide the mechanical and/or chemical properties of the composite. If the fiber volume fraction is too high, more fibers are squeezed together creating a fiber lean region near the wall and fiber rich region away from the wall. Also, the design of the injection chamber significantly affects the minimum injection pressure required to completely wet the fibers. A tapered injection chamber is considered such that wetout occurs at lower injection pressures due to the taper angle of the injection chamber. In this study, the effect of fiber volume fraction on the fiber reinforcement compaction and complete fiber wetout for a tapered injection chamber is investigated.

  17. Multimaterial preform coextrusion for robust chalcogenide optical fibers and tapers.

    PubMed

    Tao, Guangming; Shabahang, Soroush; Banaei, Esmaeil-Hooman; Kaufman, Joshua J; Abouraddy, Ayman F

    2012-07-01

    The development of robust infrared fibers is crucial for harnessing the capabilities of new mid-infrared lasers. We present a novel approach to the fabrication of chalcogenide glass fiber preforms: one-step multimaterial extrusion. The preform consists of a glass core and cladding surrounded by a built-in, thermally compatible, polymer jacket for mechanical support. Using this approach we extrude several preform structures and draw them into robust composite fibers. Furthermore, the polymer cladding allows us to produce robust tapers with submicrometer core diameter.

  18. Abrupt fiber taper based Michelson interferometric deflection sensor

    NASA Astrophysics Data System (ADS)

    Tian, Zhaobing; Yam, Scott S.-H.

    2008-06-01

    A new compact standard single mode fiber Michelson interferometer deflection sensor was proposed, tested and simulated. The new interferometer consists of a symmetrical abrupt 3 dB taper region with a 40 μm waist diameter, a 700 μm length and a 500nm thick gold layer coating. Compared with similar interferometric devices based on long period gratings that need microfabrication technology and photosensitive fibers, the proposed sensor uses a much simplified fabrication process and normal single mode fiber, and has a linear response of 1.1nm/mm.

  19. Ultraviolet-extended flat supercontinuum generation in cascaded photonic crystal fiber tapers

    NASA Astrophysics Data System (ADS)

    Chen, H. H.; Chen, Z. L.; Zhou, X. F.; Hou, J.

    2013-08-01

    Cascaded photonic crystal fiber (PCF) tapers in a monolithic fiber obtained by post-processing techniques such as hole inflation and tapering have been manufactured. An ultraviolet-extended supercontinuum (SC) generation down to 352 nm wavelength pumped at 1064 nm in cascading PCF tapers has been obtained. High spectral flatness (5 dB) has been achieved in the entire visible window.

  20. Tapered optical fiber sensor for chemical pollutants detection in seawater

    NASA Astrophysics Data System (ADS)

    Irigoyen, Maite; Sánchez-Martin, Jose Antonio; Bernabeu, Eusebio; Zamora, Alba

    2017-04-01

    Three tapered silica optical fibers, uncoated and coated with metallic (Al or Cu) and dielectric layers (TiO2), are employed to determine the presence of oil and Hazardous and Noxious Substances (HNS from now on) in water, by means of the measurement of their spectral transmittance. With our experimental assembly, the presence of oil and HNS spills can be detected employing the three different kinds of tapers, since the complete range of refractive indices of the pollutants (1.329–1.501) is covered with these tapers. The most suitable spectral range to detect the presence of a chemical pollutant in seawater has been identified and a complete spectral characterization of the three types of optical fiber tapers has been carried out. The results obtained show that, in general terms, these devices working together can be employed for the early detection of oil and HNS spills in seawater in a marine industrial environment. These sensors have many advantages, such as its low cost, its simplicity and versatility (with interesting properties as quick response and repeatability), and especially that they can be self-cleaned with seawater in motion.

  1. Magnetic field tunability of square tapered no-core fibers

    NASA Astrophysics Data System (ADS)

    Miao, Yinping; Wu, Jixuan; Lin, Wei; Zhang, Kailiang; Song, Binbin; Zhang, Hao; Liu, Bo

    2014-05-01

    A magnetic-field-tuned photonics device based on magnetic fluid (MF) and a square tapered no-core fiber (NCF) sandwiched between two single-mode fibers (SMFs) has been proposed. The enhanced evanescent field effect in the NCF is achieved by tapering the square NCF utilizing a fusion splicer. The spectral dependence of the proposed device on the applied magnetic-field intensity has been investigated. The results indicate that a maximal sensitivity of -18.7pm/Oe is obtained for a magnetic field strength ranging from 25Oe to 450Oe. The proposed tunable device has several advantages, including low cost, ease of fabrication, compact structure, and high sensitivity.

  2. Efficient sub-wavelength light confinement using surface plasmon polaritons in tapered fibers.

    PubMed

    Renna, Fabrizio; Cox, David; Brambilla, Gilberto

    2009-04-27

    Light confinement to sub-wavelength spot sizes is proposed and realized in tapered optical fibers. To achieve high transmission efficiencies, light propagating along the taper is combined with the excitation of surface plasmon polaritons (SPP) at its tip.

  3. Fabrication and characterization of bare Ge-Sb-Se chalcogenide glass fiber taper

    NASA Astrophysics Data System (ADS)

    Luo, Baohua; Wang, Yingying; Sun, Ya'nan; Dai, Shixun; Yang, Peilong; Zhang, Peiqing; Wang, Xunsi; Chen, Feifei; Wang, Rongping

    2017-01-01

    In this work, Ge15Sb20Se65 bare glass fiber with a diameter of 500 μm was fabricated, and then tapered with different tapering parameters. The analysis of Raman and energy dispersive X-ray spectra (EDS) indicated that, a slight change in the chemical composition of the glass, fiber and tapering fiber has negligible effect on the glass structure. It was found that, the waist diameter decreases exponentially with increasing tapering length and speed, and high quality taper fiber with the cone diameter of 2.65 μm can be achieved under the optimal tapering conditions. Finally, the simulated and experimental results of the output transmission under different waist length and taper ratio show that the transmission decreases with increasing waist length and taper ratio.

  4. Dual wavelength erbium-doped fiber laser using a tapered fiber

    NASA Astrophysics Data System (ADS)

    Harun, S. W.; Lim, K. S.; Jasim, A. A.; Ahmad, H.

    2010-12-01

    A tapered fiber is fabricated by heating and stretching a piece of optical fiber after the polymer protective cladding has been removed. An equidistant comb-like transmission spectrum, with a spacing of 1.6 nm and an extinction ratio of more than 5 dB, was obtained by the tapered fiber due to the multibeam interferences of the cladding modes. The tapered fiber was applied in a ring erbium-doped fiber laser (EDFL) to generate dual-wavelength lasing oscillations. The EDFL operates at wavelengths of 1557.0 nm and 1558.6 nm with a stable peak power and a signal-to-noise ratio of more than 40 dB.

  5. Carbon dioxide laser fabrication of fused-fiber couplers and tapers.

    PubMed

    Dimmick, T E; Kakarantzas, G; Birks, T A; Russell, P S

    1999-11-20

    We report the development of a fiber taper and fused-fiber coupler fabrication rig that uses a scanning, focused, CO(2) laser beam as the heat source. As a result of the pointlike heat source and the versatility associated with scanning, tapers of any transition shape and uniform taper waist can be produced. Tapers with both a linear shape and an exponential transition shape were measured. The taper waist uniformity was measured and shown to be better than +/-1.2%. The rig was also used to make fused-fiber couplers. Couplers with excess loss below -0.1 dB were routinely produced.

  6. In-situ Tapering of Chalcogenide Fiber for Mid-infrared Supercontinuum Generation

    PubMed Central

    Rudy, Charles W.; Marandi, Alireza; Vodopyanov, Konstantin L.; Byer, Robert L.

    2013-01-01

    Supercontinuum generation (SCG) in a tapered chalcogenide fiber is desirable for broadening mid-infrared (or mid-IR, roughly the 2-20 μm wavelength range) frequency combs1, 2 for applications such as molecular fingerprinting, 3 trace gas detection, 4 laser-driven particle acceleration, 5 and x-ray production via high harmonic generation. 6 Achieving efficient SCG in a tapered optical fiber requires precise control of the group velocity dispersion (GVD) and the temporal properties of the optical pulses at the beginning of the fiber, 7 which depend strongly on the geometry of the taper. 8 Due to variations in the tapering setup and procedure for successive SCG experiments-such as fiber length, tapering environment temperature, or power coupled into the fiber, in-situ spectral monitoring of the SCG is necessary to optimize the output spectrum for a single experiment. In-situ fiber tapering for SCG consists of coupling the pump source through the fiber to be tapered to a spectral measurement device. The fiber is then tapered while the spectral measurement signal is observed in real-time. When the signal reaches its peak, the tapering is stopped. The in-situ tapering procedure allows for generation of a stable, octave-spanning, mid-IR frequency comb from the sub harmonic of a commercially available near-IR frequency comb. 9 This method lowers cost due to the reduction in time and materials required to fabricate an optimal taper with a waist length of only 2 mm. The in-situ tapering technique can be extended to optimizing microstructured optical fiber (MOF) for SCG10 or tuning of the passband of MOFs, 11 optimizing tapered fiber pairs for fused fiber couplers12 and wavelength division multiplexers (WDMs), 13 or modifying dispersion compensation for compression or stretching of optical pulses.14-16 PMID:23748947

  7. Multicolor upconversion emissions in Tm 3+/Er3+ codoped tellurite photonic microwire between silica fiber tapers.

    PubMed

    Chen, Nan-Kuang; Kuan, Pei-Wen; Zhang, Junjie; Zhang, Liyan; Hu, Lili; Lin, Chinlon; Tong, Limin

    2010-12-06

    We report multicolor upconversion emissions including the blue-violet, green, and red lights in a Tm 3+/Er3+codoped tellurite glass photonic microwire between two silica fiber tapers. A silica fiber is tapered until its evanescent field is exposed and then angled-cleaved at the tapered center to divide the tapered fibers into two parts. A tellurite glass is melted by a gas flame to cluster into a sphere at the tip of one tapered fiber. The other angled-cleaved tapered fiber is blended into the melted tellurite glass. When the tellurite glass is melted, the two silica fiber tapers are simultaneously moving outwards to draw the tellurite glass into a microwire in between. The advantage of angled-cleaving on fiber tapers is to avoid cavity resonances in high index photonic microwire. Thus, the broadband white light can be transmitted between silica fibers and a special optical property like high intensity upconversion emission can be achieved. A cw 1064 nm Nd:YAG laser light is launched into the Tm 3+/Er3+ codoped tellurite microwire through a silica fiber taper to generate the multicolor upconversion emissions, including the blue-violet, green, and red lights, simultaneously.

  8. Theoretical model of the modulation transfer function for fiber optic taper

    NASA Astrophysics Data System (ADS)

    Wang, Yaoxiang; Tian, Weijian; Bin, XiangLi

    2005-02-01

    Fiber optic taper has been used more and more widely as a relay optical component in the integrated taper assembly image intensified sensors for military and medical imaging application. In this paper, the transmission characteristic of energy in the taper is analyzed, and following the generalized definition of the modulation transfer function for sampled imaging system, a spatial averaged impulse response and a corresponding MTF component that are inherent in the sampling process of taper are deduced, and the mathematical model for evaluating the modulation transfer function of fiber optic taper is built. Finally, the dynamic and static modulation transfer function curves simulated by computer have been exhibited.

  9. Gaussian Filtering with Tapered Oil-Filled Photonic Bandgap Fibers

    NASA Astrophysics Data System (ADS)

    Brunetti, A. C.; Scolari, L.; Weirich, J.; Eskildsen, L.; Bellanca, G.; Bassi, P.; Bjarklev, A.

    2008-10-01

    A tunable Gaussian filter based on a tapered oil-filled photonic crystal fiber is demonstrated. The filter is centered at λ = 1364 nm with a bandwidth (FWHM) of 237nm. Tunability is achieved by changing the temperature of the filter. A shift of 210nm of the central wavelength has been observed by increasing the temperature from 25 °C to 100 °C. The measurements are compared to a simulated spectrum obtained by means of a vectorial Beam Propagation Method model.

  10. Refractive index sensors based on the fused tapered special multi-mode fiber

    NASA Astrophysics Data System (ADS)

    Fu, Xing-hu; Xiu, Yan-li; Liu, Qin; Xie, Hai-yang; Yang, Chuan-qing; Zhang, Shun-yang; Fu, Guang-wei; Bi, Wei-hong

    2016-01-01

    In this paper, a novel refractive index (RI) sensor is proposed based on the fused tapered special multi-mode fiber (SMMF). Firstly, a section of SMMF is spliced between two single-mode fibers (SMFs). Then, the SMMF is processed by a fused tapering machine, and a tapered fiber structure is fabricated. Finally, a fused tapered SMMF sensor is obtained for measuring external RI. The RI sensing mechanism of tapered SMMF sensor is analyzed in detail. For different fused tapering lengths, the experimental results show that the RI sensitivity can be up to 444.517 81 nm/RIU in the RI range of 1.334 9—1.347 0. The RI sensitivity is increased with the increase of fused tapering length. Moreover, it has many advantages, including high sensitivity, compact structure, fast response and wide application range. So it can be used to measure the solution concentration in the fields of biochemistry, health care and food processing.

  11. Cross two photon absorption in a silicon photonic crystal waveguide fiber taper coupler with a physical junction

    SciTech Connect

    Sarkissian, Raymond O'Brien, John

    2015-01-21

    Cross two photon absorption in silicon is characterized using a tapered fiber photonic crystal silicon waveguide coupler. There is a physical junction between the tapered fiber and the waveguide constituting a stand-alone device. This device is used to obtain the spectrum for cross two photon absorption coefficient per unit volume of interaction between photons of nondegenerate energy. The corresponding Kerr coefficient per unit volume of interaction is also experimentally extracted. The thermal resistance of the device is also experimentally determined and the response time of the device is estimated for on-chip all-optical signal processing and data transfer between optical signals of different photon energies.

  12. Polarization insensitive all-fiber mode-lockers functioned by carbon nanotubes deposited onto tapered fibers

    NASA Astrophysics Data System (ADS)

    Song, Yong-Won; Morimune, Keiyo; Set, Sze Y.; Yamashita, Shinji

    2007-01-01

    The authors demonstrate a nonblocked all-fiber mode locker operated by the interaction of carbon nanotubes with the evanescent field of propagating light in a tapered fiber. Symmetric cross section of the device with the randomly oriented nanotubes guarantees the polarization insensitive operation of the pulse formation. In order to minimize the scattering, the carbon nanotubes are deposited within a designed area around the tapered waist. The demonstrated passively pulsed laser has the repetition rate of 7.3MHz and the pulse width of 829fs.

  13. Optimization of group delay response of (apodized) tapered fiber Bragg grating by shaping taper transition and apodization window

    NASA Astrophysics Data System (ADS)

    Markowski, Konrad; Jedrzejewski, Kazimierz; Osuch, Tomasz

    2016-09-01

    This article presents implementation of the Simulated Annealing (SA) algorithm for tapered fiber Bragg gratings (TFBGs) design. Particularly, together with well-known Coupled Mode Theory (CMT) and Transfer Matrix Method (TMM) the algorithm optimizes the group delay response of TFBG, by simultaneous shaping of both apodization function and tapered fiber transition profile. Prior to the optimization process, numerical model for TFBG design has been validated. Preliminary results reveal great potential of the SA-based approach and with proper definition of the design criteria may be even applied for optimization of the spectral properties of TFBGs.

  14. Novel methods for measuring modulation transfer function for fiber optic taper

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Wang, Yaoxiang; Tian, Weijian; Ma, Weihong; Zhang, Hongjian; Sun, Aijuan

    2006-01-01

    As a relay optical component, fiber optic taper has become more important and more widely used in the integrated taper assembly image intensified sensors for military and medical imaging application. However, the method for evaluating the quality of output images from the fiber optic taper is few. In this article, the Modulation Transfer Function (MTF) is introduced and measured to evaluate the image quality of fiber optic taper. Because fiber optic taper is of a mosaic array architecture, there are some new problems need to be resolved in defining MTF of it. And there also should be some special requirements in MTF measurement. Two methods including edge scanning and point imaging analyzing are introduced in measuring MTF of fiber optic taper, in which the incident light, scanning step and scanning range are specially limited. Experiments show that the results of the measurements consist with the theoretical analysis simulated by computer. And the spatial averaged MTF of fiber optic taper has been gotten by two means. It is concluded that the MTF value measured by point imaging is always some higher than measured by edge scanning, because the point imaging is more weakly effected by the fiber arrangement in taper.

  15. Fusion splice between tapered inhibited coupling hypocycloid-core Kagome fiber and SMF.

    PubMed

    Zheng, Ximeng; Debord, Benoît; Vincetti, Luca; Beaudou, Benoît; Gérôme, Frédéric; Benabid, Fetah

    2016-06-27

    We report for the first time on tapering inhibited coupling (IC) hypocycloid-core shape Kagome hollow-core photonic crystal fibers whilst maintaining their delicate core-contour negative curvature with a down-ratio as large as 2.4. The transmission loss of down-tapered sections reaches a figure as low as 0.07 dB at 1550 nm. The tapered IC fibers are also spliced to standard SMF with a total insertion loss of 0.48 dB. These results show that all-fiber photonic microcells with the ultra-low loss hypocycloid core-contour Kagome fibers is now possible.

  16. Tapered Polymer Fiber Sensors for Reinforced Concrete Beam Vibration Detection.

    PubMed

    Luo, Dong; Ibrahim, Zainah; Ma, Jianxun; Ismail, Zubaidah; Iseley, David Thomas

    2016-12-16

    In this study, tapered polymer fiber sensors (TPFSs) have been employed to detect the vibration of a reinforced concrete beam (RC beam). The sensing principle was based on transmission modes theory. The natural frequency of an RC beam was theoretically analyzed. Experiments were carried out with sensors mounted on the surface or embedded in the RC beam. Vibration detection results agreed well with Kistler accelerometers. The experimental results found that both the accelerometer and TPFS detected the natural frequency function of a vibrated RC beam well. The mode shapes of the RC beam were also found by using the TPFSs. The proposed vibration detection method provides a cost-comparable solution for a structural health monitoring (SHM) system in civil engineering.

  17. Tapered Polymer Fiber Sensors for Reinforced Concrete Beam Vibration Detection

    PubMed Central

    Luo, Dong; Ibrahim, Zainah; Ma, Jianxun; Ismail, Zubaidah; Iseley, David Thomas

    2016-01-01

    In this study, tapered polymer fiber sensors (TPFSs) have been employed to detect the vibration of a reinforced concrete beam (RC beam). The sensing principle was based on transmission modes theory. The natural frequency of an RC beam was theoretically analyzed. Experiments were carried out with sensors mounted on the surface or embedded in the RC beam. Vibration detection results agreed well with Kistler accelerometers. The experimental results found that both the accelerometer and TPFS detected the natural frequency function of a vibrated RC beam well. The mode shapes of the RC beam were also found by using the TPFSs. The proposed vibration detection method provides a cost-comparable solution for a structural health monitoring (SHM) system in civil engineering. PMID:27999245

  18. Research on taper zone coupling from single-core fiber to annular-core hollow beam fiber

    NASA Astrophysics Data System (ADS)

    Tong, Chengguo; Zhang, Tao; Li, Jianqi; Wang, Pengfei; Kang, Chong; Yuan, Libo

    2017-02-01

    We designed and manufactured a novel annular-core hollow beam fiber which could directly yield ring light with a central dark spot inside the beam employing MCVD technique and a custom-made fiber drawing tower. The tapered fiber zone geometric shapes at varied stretching speed between the single-core fiber and the annular-core hollow beam fiber were studied theoretically. According to the beam propagation method, the bi-tapered coupling energy transmission between these two fibers was simulated and analyzed. Moreover, by adopting a fusion splicing and stretching technique at the fiber-linked point, an effective coupling approach had been fulfilled.

  19. Research on taper zone coupling from single-core fiber to annular-core hollow beam fiber

    NASA Astrophysics Data System (ADS)

    Tong, Chengguo; Zhang, Tao; Li, Jianqi; Wang, Pengfei; Kang, Chong; Yuan, Libo

    2016-11-01

    We designed and manufactured a novel annular-core hollow beam fiber which could directly yield ring light with a central dark spot inside the beam employing MCVD technique and a custom-made fiber drawing tower. The tapered fiber zone geometric shapes at varied stretching speed between the single-core fiber and the annular-core hollow beam fiber were studied theoretically. According to the beam propagation method, the bi-tapered coupling energy transmission between these two fibers was simulated and analyzed. Moreover, by adopting a fusion splicing and stretching technique at the fiber-linked point, an effective coupling approach had been fulfilled.

  20. Temperature-independent gas refractometer based on an S-taper fiber tailored fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Shao, Zhihua; Qiao, Xueguang; Bao, Weijia; Rong, Qiangzhou

    2016-09-01

    A fiber Bragg grating (FBG)-based gas refractometer is proposed and demonstrated experimentally. The configuration consists of a short section of S-type taper incorporated in the upstream of a FBG. The S-taper is capable to couple the core mode to cladding modes into the downstream single mode fiber (SMF), and the low-order cladding modes can be reflected back to the fiber core via the FBG. Because of the recoupling efficiency depending on surrounding refractive index (SRI), the reflection power of the device presents high response to gas RI change with the sensitivity of 172.7 dB/RIU. This power-referenced RI measurement and wavelength-referenced temperature measurement have been achieved via selective cladding modes monitoring.

  1. Characterization of arbitrary fiber taper profiles with optical microscopy and image processing algorithms

    NASA Astrophysics Data System (ADS)

    Farias, Heric D.; Sebem, Renan; Paterno, Aleksander S.

    2014-08-01

    This work reports results from the development of a software to process the parameters involved in the characterization of fiber taper profiles, while using optical microscopy, a high-definition camera and a high- precision translation stage as the moveable base on which the taper is positioned. In addition to this procedure, image processing algorithms were customized to process the acquired images. With edge detection algorithms in the stitched image, one would be able to characterize the given taper radius curve that represents the taper profile when the camera has a sufficient resolution. As a consequence, the proposed fiber taper characterization procedure is a first step towards a high-resolution characterization of fiber taper diameters with arbitrary profiles, specially this case, in which tapers are fabricated with the stepwise technique that allows the production of non- biconical profiles. The parameters of the stitched images depends on the used microscope objective and the length of the characterized tapers. A non-biconical arbitrary taper is measured as an example for the illustration of the developed software and procedure.

  2. Multiplex and simultaneous measurement of displacement and temperature using tapered fiber and fiber Bragg grating

    SciTech Connect

    Ji Chongke; Zhao Chunliu; Kang Juan; Dong Xinyong; Jin Shangzhong

    2012-05-15

    A simple method to work out the multiplexing of tapered fiber based sensors is proposed and demonstrated. By cascading a tapered fiber with a fiber Bragg grating (FBG), the sensor head is provided with a wavelength identification, different FBGs provide the sensor heads with different reflective peaks and they can be distinguished in optical spectrum. By compositing several such sensor heads with a multi-channel beam splitter, a star-style topological structure sensor for multipoint sensing is achieved. At the same time, the output intensity at the peak wavelength is sensitive to one external physical parameter applied on the related FBG-cascaded tapered fiber and the central wavelength of the peak is only sensitive to temperature, so that that parameter and temperature can be measured simultaneously. A sensor for dual-point measurement of the displacement and temperature simultaneously is experimentally demonstrated by using a 2 x 2 coupler in this paper. Experiment results show that the sensor works well and the largest sensitivities reach to 0.11 dB/{mu}m for displacement in the range of 0-400 {mu}m, and {approx}0.0097 nm/ deg. C for temperature between 20 deg. C and 70 deg. C.

  3. Coupling of single NV center to adiabatically tapered optical single mode fiber

    NASA Astrophysics Data System (ADS)

    Vorobyov, Vadim V.; Soshenko, Vladimir V.; Bolshedvorskii, Stepan V.; Javadzade, Javid; Lebedev, Nikolay; Smolyaninov, Andrey N.; Sorokin, Vadim N.; Akimov, Alexey V.

    2016-12-01

    We demonstrated a simple and reliable technique of coupling diamond nanocrystal containing NV center to tapered optical fiber. The NV center emission was collected by the fiber via nearfield interaction between NV center and the tapered portion of the fiber. Single photon statistics was demonstrated at the fiber end as well as up to 3 times improvement in collection efficiency with respect to our confocal microscope. Also, we carefully studied fluorescence of the fiber itself and were able to suppress it to the level lower than single photon emission from the NV center.

  4. Trapping and propelling microparticles at long range by using an entirely stripped and slightly tapered no-core optical fiber.

    PubMed

    Sheu, Fang-Wen; Huang, Yen-Si

    2013-02-28

    A stripped no-core optical fiber with a 125 µm diameter was transformed into a symmetric and unbroken optical fiber that tapers slightly to a 45-µm-diameter waist. The laser light can be easily launched into the no-core optical fiber. The enhanced evanescent wave of the slightly tapered no-core optical fiber can attract nearby 5-µm-diameter polystyrene microparticles onto the surface of the tapered multimode optical fiber within fast flowing fluid and propel the trapped particles in the direction of the light propagation to longer delivery range than is possible using a slightly tapered telecom single-mode optical fiber.

  5. Supercontinuum generation from 437 to 2850 nm in a tapered fluorotellurite microstructured fiber

    NASA Astrophysics Data System (ADS)

    Wang, F.; Jia, Z. X.; Yao, C. F.; Wang, S. B.; Hu, M. L.; Wu, C. F.; Ohishi, Y.; Qin, W. P.; Qin, G. S.

    2016-12-01

    We demonstrated supercontinuum (SC) generation in a tapered fluorotellurite microstructured fiber (MF) with a sub-micrometer core diameter. Fluorotellurite MFs based on TeO2-BaF2-Y2O3 glasses were fabricated by using a rod-in-tube method and a tapered fluorotellurite MF with a minimum core diameter of ~0.65 µm was prepared by employing a tapering system. A 1560 nm femtosecond fiber laser was used as the pumping source. With increasing the peak power of the launched pump laser to ~11 kW, SC light expanding from 437 to 2850 nm was generated in the tapered fluorotellurite MF. In addition, relatively strong blue-shifted dispersive wave at ~489 nm was also observed from the tapered fluorotellurite MF.

  6. Optical similaritons in a tapered graded-index nonlinear-fiber amplifier with an external source

    SciTech Connect

    Raju, Thokala Soloman; Panigrahi, Prasanta K.

    2011-09-15

    We analytically explore a wide class of optical similariton solutions to the nonlinear Schroedinger equation appropriately modified to model beam propagation in a tapered, graded-index nonlinear-fiber amplifier with an external source. Under certain physical conditions, we reduce the coupled nonlinear Schroedinger equations to a single-wave equation that aptly describes similariton propagation through asymmetric twin-core fiber amplifiers. The asymmetric twin-core fiber is composed of two adjoining, closely spaced, single-mode fibers in which the active one is a tapered, graded-index nonlinear-fiber and the passive one is a step-index fiber. We obtain these self-similar waves for different choices of tapered index profile, using a Moebius transformation. Our procedure is applicable for both self-focusing and self-defocusing nonlinearities.

  7. Tapered optical fiber tip probes based on focused ion beam-milled Fabry-Perot microcavities

    NASA Astrophysics Data System (ADS)

    André, Ricardo M.; Warren-Smith, Stephen C.; Becker, Martin; Dellith, Jan; Rothhardt, Manfred; Zibaii, M. I.; Latifi, H.; Marques, Manuel B.; Bartelt, Hartmut; Frazão, Orlando

    2016-09-01

    Focused ion beam technology is combined with dynamic chemical etching to create microcavities in tapered optical fiber tips, resulting in fiber probes for temperature and refractive index sensing. Dynamic chemical etching uses hydrofluoric acid and a syringe pump to etch standard optical fibers into cone structures called tapered fiber tips where the length, shape, and cone angle can be precisely controlled. On these tips, focused ion beam is used to mill several different types of Fabry-Perot microcavities. Two main cavity types are initially compared and then combined to form a third, complex cavity structure. In the first case, a gap is milled on the tapered fiber tip which allows the external medium to penetrate the light guiding region and thus presents sensitivity to external refractive index changes. In the second, two slots that function as mirrors are milled on the tip creating a silica cavity that is only sensitive to temperature changes. Finally, both cavities are combined on a single tapered fiber tip, resulting in a multi-cavity structure capable of discriminating between temperature and refractive index variations. This dual characterization is performed with the aid of a fast Fourier transform method to separate the contributions of each cavity and thus of temperature and refractive index. Ultimately, a tapered optical fiber tip probe with sub-standard dimensions containing a multi-cavity structure is projected, fabricated, characterized and applied as a sensing element for simultaneous temperature and refractive index discrimination.

  8. Dual-parameter optical fiber sensor based on concatenated down-taper and multimode fiber

    NASA Astrophysics Data System (ADS)

    Tong, Zhengrong; Luan, Panpan; Cao, Ye; Zhang, Weihua; Su, Jun

    2016-01-01

    A novel dual-parameter optical fiber sensor based on a single-mode fiber (SMF) down-taper and multimode fiber (MMF) is proposed and demonstrated. The sensor structure is formed by cascading a down-taper and MMF through a segment of SMF. The transmission spectrum exhibits response of the interference between core and different cladding modes. Two interference dips can be observed within a certain range of detection. Due to the different wavelength shifts of the selected two dips, simultaneous measurement of temperature and liquid level can be achieved. Experiment results indicate a good linear relation between the wavelength shift and external parameters (temperature and liquid level). The measured temperature sensitivities are 0.02 nm/°C and 0.031 nm/°C, and liquid level sensitivities are 0.022 nm/mm and 0.07 nm/mm, respectively. In addition, the fiber sensor has the advantages of compact size, simple fabrication and cost-effective.

  9. Initiatory concept of localized CO2 laser-based tapering rig for realization of in-fiber devices

    NASA Astrophysics Data System (ADS)

    Aharoni, Ran; Bidani, Liron; Sinvani, Moshe; Zalevsky, Zeev

    2012-07-01

    We present the development procedure as well as preliminary fabrication results for a CO2 laser-based tapering rig allowing one stage tapering of optical fibers. Our aim is to develop in-fiber devices constructed from fibers filled with various materials, which can be drawn from thick preforms using the presented procedure. The constructed tapering rig consists of a CO2 laser as the heating source, ellipsoid-based mirror optics, and computer-controlled high-precision motors.

  10. Optical flowmeter using a modal interferometer based on a single nonadiabatic fiber taper.

    PubMed

    Frazão, O; Caldas, P; Araújo, F M; Ferreira, L A; Santos, J L

    2007-07-15

    A novel in-fiber modal interferometer is presented that is based on a nonadiabatic biconical fused taper that couples light between the cladding and the core, combined with the Fresnel reflection at the fiber end. It is observed that the returned light from this fiber structure shows a channeled spectrum similar to that of a two-wave Michelson interferometer. The application of this device as a fiber optic flowmeter sensor is demonstrated.

  11. Miniature tapered photonic crystal fiber interferometer with enhanced sensitivity by acid microdroplets etching.

    PubMed

    Qiu, Sun-jie; Chen, Ye; Kou, Jun-long; Xu, Fei; Lu, Yan-qing

    2011-08-01

    We fabricate a miniature tapered photonic crystal fiber (PCF) interferometer with enhanced sensitivity by acid microdroplets etching. This method is very simple and cost effective, avoiding elongating the PCF, moving and refixing the device during etching, and measuring. The refractive index sensing properties with different PCF diameters are investigated both theoretically and experimentally. The tapering velocity can be controlled by the microdroplet size and position. The sensitivity greatly increases (five times, 750 nm/RIU) and the size decreases after slightly tapering the PCF. The device keeps low temperature dependence before and after tapering. More uniformly and thinly tapered PCFs can be realized with higher sensitivity (∼100 times) by optimizing the etching process.

  12. All fiber magnetic field sensor with Ferrofluid-filled tapered microstructured optical fiber interferometer.

    PubMed

    Deng, Ming; Huang, Can; Liu, Danhui; Jin, Wei; Zhu, Tao

    2015-08-10

    An ultra-compact optical fiber magnetic field sensor based on a microstructured optical fiber (MOF) modal interference and ferrofluid (FF) has been proposed and experimentally demonstrated. The magnetic field sensor was fabricated by splicing a tapered germanium-doped index guided MOF with six big holes injected with FF to two conventional single-mode fibers. The transmission spectra of the proposed sensor under different magnetic field intensities have been measured and theoretically analyzed. Due to an efficient interaction between the magnetic nanoparticles in FF and the excited cladding mode, the magnetic field sensitivity reaches up to117.9pm/mT with a linear range from 0mT to 30mT. Moreover, the fabrication process of the proposed sensor is simple, easy and cost-effective. Therefore, it will be a promising candidate for military, aviation industry, and biomedical applications, especially, for the applications where the space is limited.

  13. A refractive index sensor based on taper Michelson interferometer in multimode fiber

    NASA Astrophysics Data System (ADS)

    Fu, Xinghu; Zhang, Jiangpeng; Wang, Siwen; Fu, Guangwei; Liu, Qiang; Jin, Wa; Bi, Weihong

    2016-11-01

    A refractive index sensor based on taper Michelson interferometer in multimode fiber is proposed. The Hydrofluoric acid corrosion processing is studied in the preparation of single cone multimode optical fiber sensor. The taper Michelson interferometer is fabricated by changing corrosion time. The relationship between fiber sensor feature and corrosion time is analyzed. The experimental results show that the interference spectrum shift in the direction of short wave with the increase of the refractive index. The refractive index sensitivity can reach 115.8008 nm/RIU. Thereby, it can be used in detecting the refractive index in different areas including the environmental protection, health care and food production.

  14. Tailored dispersion profile in controlling optical solitons in a tapered parabolic index fiber

    NASA Astrophysics Data System (ADS)

    Prakash, S. Arun; Malathi, V.; Mani Rajan, M. S.

    2016-03-01

    We investigate the soliton dynamics in tapered parabolic index fibers via symbolic computation for a variety of dispersion profiles to inspect how a specific dispersion profile controls the optical soliton. By means of AKNS procedure, Lax pair is constructed for nonlinear Schrödinger equation with variable coefficients. Using obtained Lax pair, multi-soliton solutions are generated via Darboux transformation technique. Using multi-soliton solutions, soliton dynamics in tapered parabolic index fiber with the hyperbolic, Gaussian, exponential, and linear profiles are discussed. Results obtained in this study will be of certain potential application on construction of the nonlinear optical devices by soliton control. Results obtained in this study will be of certain value to the studies on the propagation and application of the soliton in the tapered parabolic index fiber and dispersion-managed fiber system.

  15. High-sensitivity refractive index sensors based on fused tapered photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Fu, Xing-hu; Xie, Hai-yang; Yang, Chuan-qing; Qu, Yu-wei; Zhang, Shun-yang; Fu, Guang-wei; Guo, Xuan; Bi, Wei-hong

    2016-05-01

    In this paper, a novel liquid refractive index (RI) sensor based on fused tapered photonic crystal fiber (PCF) is proposed. It is fabricated by fusing and tapering a section of PCF which is spliced with two single-mode fibers (SMFs). Due to the fused biconical taper method, the sensor becomes longer and thinner, to make the change of the outside RI has more direct effects on the internal optical field of the PCF, which finally enhances the sensitivity of this sensor. Experimental results show that the transmission spectra of the sensor are red-shifted obviously with the increase of RI. The longer the tapered region of the sensor, the higher the sensitivity is. This sensor has the advantages of simple structure, easy fabrication, high performance and so on, so it has potential applications in RI measurement.

  16. All-fiber magnetic field sensor based on tapered thin-core fiber and magnetic fluid.

    PubMed

    Zhang, Junying; Qiao, Xueguang; Yang, Hangzhou; Wang, Ruohui; Rong, Qiangzhou; Lim, Kok-Sing; Ahmad, Harith

    2017-01-10

    A method for the measurement of a magnetic field by combining a tapered thin-core fiber (TTCF) and magnetic fluid is proposed and experimentally demonstrated. The modal interference effect is caused by the core mode and excited eigenmodes in the TTCF cladding. The transmission spectra of the proposed sensor are measured and theoretically analyzed at different magnetic field strengths. The results field show that the magnetic sensitivity reaches up to -0.1039  dB/Oe in the range of 40-1600 e. The proposed method possesses high sensitivity and low cost compared with other expensive methods.

  17. Low-temperature sensitivity periodically tapered photonic crystal-fiber-based refractometer.

    PubMed

    Wang, Pengfei; Bo, Lin; Guan, Chunying; Semenova, Yuliya; Wu, Qiang; Brambilla, Gilberto; Farrell, Gerald

    2013-10-01

    In this Letter, an all-fiber refractometer with a simple configuration of periodical tapers on a photonic crystal fiber (PCF) is proposed and investigated experimentally. The proposed fiber refractive index (RI) sensor consists of a PCF sandwiched between two standard single-mode fibers, with tapers periodically fabricated along the PCF using a CO(2) laser beam focused by a ZnSe cylindrical lens. The proposed fiber sensor can be used for RI sensing by measuring the wavelength shift of the multimode interference dip over the transmission spectrum. An average sensitivity of 222 nm/RIU has been experimentally achieved over a RI range from 1.33 to 1.38. The proposed refractometer is also significantly less sensitive to temperature, and an experimental demonstration of this reduced sensitivity is presented. The proposed RI sensor benefits from simplicity and low-cost and achieves a competitive sensitivity compared with other existing fiber-optic sensors.

  18. Bent optical fiber tapers for refractometery and biosensing

    NASA Astrophysics Data System (ADS)

    Penchev, Emil; Eftimov, Tinko; Bock, Wojtek

    2015-01-01

    We report the results of our study of the spectral shifts caused by surrounding refractive index changes (SRI) in bent fibre tapers. Fused and etched fibre tapers were fabricated using a gas burner and HF acid. Spectral shifts as high as 200 nm have been observed for SRI variations from 1.33 to 1.44 and sensitivity as high as 830 nm/r.i.u. around water RI values. We present results for refractometric measurements of cow milk of varying fat content and compare results with those obtained with conventional Abbe refractometers and high sensitivity double resonance LPGs.

  19. Ultrathin fiber-taper coupling with nitrogen vacancy centers in nanodiamonds at cryogenic temperatures.

    PubMed

    Fujiwara, Masazumi; Zhao, Hong-Quan; Noda, Tetsuya; Ikeda, Kazuhiro; Sumiya, Hitoshi; Takeuchi, Shigeki

    2015-12-15

    We demonstrate cooling of ultrathin fiber tapers coupled with nitrogen vacancy (NV) centers in nanodiamonds to cryogenic temperatures. Nanodiamonds containing multiple NV centers are deposited on the subwavelength 480-nm-diameter nanofiber region of fiber tapers. The fiber tapers are successfully cooled to 9 K using our home-built mounting holder and an optimized cooling speed. The fluorescence from the nanodiamond NV centers is efficiently channeled into a single guided mode and shows characteristic sharp zero-phonon lines (ZPLs) of both neutral and negatively charged NV centers. The present nanofiber/nanodiamond hybrid systems at cryogenic temperatures can be used as NV-based quantum information devices and for highly sensitive nanoscale magnetometry in a cryogenic environment.

  20. Temperature sensor based on a tapered optical fiber with ALD nanofilm

    NASA Astrophysics Data System (ADS)

    Zhu, Shan; Pang, Fufei; Wen, Jianxiang; Zhao, Ziwen; Wang, Tingyun

    2015-09-01

    A temperature sensor with high sensitivity based on a tapered optical fiber with Al2O3 nanofilm by atomic layer deposition (ALD) technology is presented. Attributed to the high refractive index Al2O3 nanofilm overlay, an asymmetry Fabry-Perot interferometer is formed along the tapered fiber. Based on the ray-optic analysis, the resonant dip in the interference transmission spectrum depends on the phase delay variation induced by the Goos-Hänchen shift at the nanofilm-coating interface. As a result, the interference transmission spectrum shows good sensitivity to the change of surrounding refractive index. In this work, a temperature-sensitive silicone gel is coated around the fiber taper with Al2O3 nanofilm to realize a high sensitivity temperature sensor. The high sensitivity of 2.44 nm/°C is obtained.

  1. Manipulating multiparticles simultaneously with tapered-tip single fiber optical tweezers

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Wu, Zhongfu; Liu, Zhihai; Yang, Jun; Yuan, Libo

    2008-12-01

    We present a single-core tapered-tip single fiber optical tweezers, which can trap multi-particle simultaneously. In order to test and verify its new function, finite difference time domain (FDTD) method is used to calculate and simulate. The relationship between the trapping force and the particle-parameters, such as the size, refractive index and others of particle are studied. By experimental validation, the tapered-tip single optic fiber tweezers can trap Particle 2nd after the Particle 1st trapped firmly, but can not trap Particle 3rd, which just verifies the theoretical simulation results to be right.

  2. Directional anemometer based on an anisotropic flat-clad tapered fiber Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Lee, Cheng-Ling; Lee, Chung-Fen; Li, Chai-Ming; Chiang, Tsai-Ching; Hsiao, Ying-Li

    2012-07-01

    This work demonstrates a sensitive directional anemometer that is based on a pendulum-type of anisotropic flat-clad tapered fiber Michelson interferometer (AFCTFMI). The AFCTFMI is fabricated by tapering an anisotropic flat-cladding fiber to establish structural anisotropy, and enables the sensing of the direction and magnitude of flowing air (wind). Wavelength shifts and fringes visibility of the measured interference fringes are correlated with the magnitude and furthermore the direction of the wind. Experimental results agree closely with the theoretical analysis. The directional anemometer can simultaneously and effectively indicate the direction, and sensitively measure the magnitude of wind.

  3. Power coupling in multicore optical fiber tapers utilizing out-cladding ferrofluids

    NASA Astrophysics Data System (ADS)

    Tagoudi, Eirini; Milenko, Karolina; Pissadakis, Stavros

    2016-04-01

    Herein we present the experimental implementation of a power coupling device that combines the technology of tapered, multicore microstructured optical fibres (MOFs) with ferrofluidic overlayers. Power coupling between different cores of a tapered, multicore MOF is demonstrated, utilizing magneto-refraction effects induced by magnetic field stimulus into a ferrofluidic outcladding surrounding of the multicore optical fibre taper. By tapering the multicore all-solid MOF to a specific diameter, the excitation of all the adjacent cores through the central one is achieved. Transmission spectra measurements of the individual cores proved that light coupling between fiber cores can be manipulated by magnetic field stimulus. We anticipate that such a type of magneto-tunable power-coupling photonic device can find applications in optical magnetometry, imaging and optical communications.

  4. Octave-spanning spectrum generation in tapered silica photonic crystal fiber by Yb:fiber ring laser above 500 MHz.

    PubMed

    Jiang, Tongxiao; Wang, Guizhong; Zhang, Wei; Li, Chen; Wang, Aimin; Zhang, Zhigang

    2013-02-15

    We report octave-spanning spectrum generated in a tapered silica photonic crystal fiber by a mode-locked Yb:fiber ring laser at a repetition rate as high as 528 MHz. The output pulses from this laser were compressed to 62 fs. By controlling the hole expansion and core diameter, a silica PCF was tapered to 20 cm with an optimal d/Λ ratio of 0.6. Pulses with the energy of 280 pJ and the peak power of 4.5 kW were injected into the tapered fiber and the pulse spectrum was expanded from 500 to 1600 nm at the level of -30 dB.

  5. A long uniform taper applied to an all-fiber Tm3+ doped double-clad fiber laser

    NASA Astrophysics Data System (ADS)

    Zhang, Y. J.; Zhong, F. F.; He, W. B.; Zhang, Y.; Wang, Y.; Xu, J.; Ju, Y. L.

    2010-11-01

    A long uniform taper fabricated on a large mode area Tm3+-doped double-clad fiber laser, which was clad-pumped by a laser diode (LD), was found to be an effective wavelength filter while improving the output beam quality and narrowing the line-width significantly. The long uniform taper was fabricated directly on the multi-mode Tm3+-doped fiber by heating and stretching method, and located several centimeters before the output fiber end. By slightly bending the taper section, the output laser spectrum was left with only one peak with a line-width less than 0.5 nm, compared to the multi-peak spectrum with a 5 nm line-width before tapering, indicating that the multi-mode fiber could produce quasi-single wavelength output with a long uniform taper. The beam quality factor M 2 declined from 6.6 to 2.6 compared. Only a slight decrease in slope efficiency, from 19.2 to 17.5%, was observed. The main output wavelength had a blue shift of 8 nm.

  6. The observation of comblike transmission spectrum from a tapered single mode fiber tip

    NASA Astrophysics Data System (ADS)

    Li, Y.; Bao, X.

    2008-12-01

    Tapered fiber tips are fabricated by the fast stretching of a heated single mode fiber until it breaks. As the fiber tip diameter decreases, the propagation mode converts from the single core mode to a few cladding modes. The cladding modes are then emitted from the fiber tip and interfere with each other in the near field. Along the propagation direction, the optical field is found to be modulated due to multibeam interferences. Interestingly, broadband transmission spectrums show equidistant comblike peaks. A tunable spatial filter based on a fiber tip is realized to reshape a broadband light source.

  7. Evaluation of the tapered PMMA fiber sensor response due to the ionic interaction within electrolytic solutions

    NASA Astrophysics Data System (ADS)

    Batumalay, M.; Rahman, H. A.; Kam, W.; Ong, Y. S.; Ahmad, F.; Zakaria, R.; Harun, S. W.; Ahmad, H.

    2014-01-01

    A tapered plastic multimode fiber (PMMA) optical sensor is proposed and demonstrated for continuous monitoring of solutions based on different concentration of sodium chloride and glucose in deionized water The tapered PMMA fiber was fabricated using an etching method involving deionized water and acetone to achieve a waist diameter and length of 0.45 mm and 10 mm, respectively, and was used to investigate the effect of straight, U-shape, and knot shape against concentration for both sodium chloride and glucose. The results show that there is a strong dependence of the electrolytic and non-electrolytic nature of the chemical solutions on the sensor output. It is found that the sensitivity of the sodium chloride concentration sensor with the straight tapered fiber probe was 0.0023 mV/%, which was better than the other probe arrangements of U-shape and knot. Meanwhile, the glucose sensor performs with the highest sensitivity of 0.0026 mV/wt % with the knot-shaped tapered fiber probe. In addition, a tapered PMMA probe which was coated by silver film was fabricated and demonstrated using calcium hypochlorite (G70) solution. The working mechanism of such a device is based on the observed increment in the transmission of the sensor that is immersed in solutions of higher concentration. As the concentration varies from 0 ppm to 6 ppm, the output voltage of the sensor increases linearly from 3.61 mV to 4.28 mV with a sensitivity of 0.1154 mV/ppm and a linearity of more than 99.47%. The silver film coating increases the sensitivity of the proposed sensor due to the effective cladding refractive index, which increases with the coating and thus allows more light to be transmitted from the tapered fiber.

  8. All-fiber-integrated single frequency tapered fiber amplifier with near diffraction limited output

    NASA Astrophysics Data System (ADS)

    Zhou, Zichao; Zhang, Hanwei; Wang, Xiaolin; Pan, Zhiyong; Su, Rongtao; Yang, Baolai; Zhou, Pu; Xu, Xiaojun

    2016-06-01

    We present an all-fiber single frequency high-power amplifier using tapered ytterbium-doped fiber (T-YDF) based on a master oscillator power amplification (MOPA) scheme. Different from previous laser amplifiers, the monolithic system is all-fiber-integrated, employing a large mode area (LMA) T-YDF and co-pump scheme. The LMA T-YDF is 7 m long and its core/inner cladding diameters are 20.4/237.1 μm and 46.9/579.9 μm in the input port and output port, respectively. In experiment, the laser amplifier is shown to generate up to 53 W of single frequency laser with slope efficiency of 57.7%, which indicates more than a two times increase of the stimulated Brillouin scattering (SBS) threshold than common LMA fibers with core/inner cladding diameters of 20/400 μm. At the highest output power, the M 2 factor is measured to be 1.25 and 1.20 in the X and Y directions. Results show that this T-YDF can be scaled up to even higher power when other SBS suppression methods are employed simultaneously.

  9. Trench-embedding fiber taper sensor fabricated by a femtosecond laser for gas refractive index sensing.

    PubMed

    Cao, Zhitao; Jiang, Lan; Wang, Sumei; Wang, Peng; Zhang, Fei; Lu, Yongfeng

    2014-02-20

    A fiber in-line, multimode coupling interferometer with a trench-embedding, fiber taper probe is proposed and fabricated by femtosecond-laser-induced water breakdown. The reflection-type taper probe is used for gas refractive index (RI) detection from 1.0001143 to 1.0002187 and temperature sensing from 50°C to 500°C. The largest RI sensitivity of the taper probe embedded with a trench at a width of 18.4 μm is 669.502  nm/RIU for hybrid nitrogen and helium. Temperature sensitivity is 9.97  pm/°C and it shows good linearity through the whole testing range. The new-type multimode interferometer is appropriate for high-accuracy gas RI detection of micrometer-scale spaces and wide-range temperature compensation can be realized.

  10. Diaphragm-free fiber-optic Fabry-Perot interferometer based on tapered hollow silica tube

    NASA Astrophysics Data System (ADS)

    Fang, Guocheng; Jia, Pinggang; Liang, Ting; Tan, Qiulin; Hong, Yingping; Liu, Wenyi; Xiong, Jijun

    2016-07-01

    A miniature fiber-optic Fabry-Perot interferometer fabricated by splicing a diaphragm-free hollow silica tube to a single-mode fiber and fusing the inner core to a taper is presented. The tapered zone forces lights to propagate from the fiber core into the silica tube, and the lights is reflected from the end faces of the optical fiber and the hollow silica tube. The contrast ratio of the interference fringe is determined by the minimum inner diameter of hollow silica tube. The responses of the proposed interferometer to high-temperature, gas refractive index, liquid refractive index and pressure were measured and were found to be linear with sensitivities of 16.26 pm/°C, 610.47 nm/RIU, -122.36 dB/RIU and 1.56 pm/kPa, respectively.

  11. Dynamic Response of Tapered Optical Multimode Fiber Coated with Carbon Nanotubes for Ethanol Sensing Application

    PubMed Central

    Shabaneh, Arafat; Girei, Saad; Arasu, Punitha; Mahdi, Mohd; Rashid, Suraya; Paiman, Suriati; Yaacob, Mohd

    2015-01-01

    Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT) thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%), the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s) towards ethanol. PMID:25946634

  12. Dynamic response of tapered optical multimode fiber coated with carbon nanotubes for ethanol sensing application.

    PubMed

    Shabaneh, Arafat; Girei, Saad; Arasu, Punitha; Mahdi, Mohd; Rashid, Suraya; Paiman, Suriati; Yaacob, Mohd

    2015-05-04

    Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT) thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%), the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s) towards ethanol.

  13. High Sensitivity Refractometer Based on TiO₂-Coated Adiabatic Tapered Optical Fiber via ALD Technology.

    PubMed

    Zhu, Shan; Pang, Fufei; Huang, Sujuan; Zou, Fang; Guo, Qiang; Wen, Jianxiang; Wang, Tingyun

    2016-08-15

    Atomic layer deposition (ALD) technology is introduced to fabricate a high sensitivity refractometer based on an adiabatic tapered optical fiber. Different thicknesses of titanium dioxide (TiO₂) nanofilm were coated around the tapered fiber precisely and uniformly under different deposition cycles. Attributed to the higher refractive index of the TiO₂ nanofilm compared to that of silica, an asymmetric Fabry-Perot (F-P) resonator could be constructed along the fiber taper. The central wavelength of the F-P resonator could be controlled by adjusting the thickness of the TiO₂ nanofilm. Such a F-P resonator is sensitive to changes in the surrounding refractive index (SRI), which is utilized to realize a high sensitivity refractometer. The refractometer developed by depositing 50.9-nm-thickness TiO₂ on the tapered fiber shows SRI sensitivity as high as 7096 nm/RIU in the SRI range of 1.3373-1.3500. Due to TiO₂'s advantages of high refractive index, lack of toxicity, and good biocompatibility, this refractometer is expected to have wide applications in the biochemical sensing field.

  14. Refractive index sensor based on an abrupt taper Michelson interferometer in a single-mode fiber.

    PubMed

    Tian, Zhaobing; Yam, Scott S-H; Loock, Hans-Peter

    2008-05-15

    A simple refractive index sensor based on a Michelson interferometer in a single-mode fiber is constructed and demonstrated. The sensor consists of a single symmetrically abrupt taper region in a short piece of single-mode fiber that is terminated by approximately 500 nm thick gold coating. The sensitivity of the new sensor is similar to that of a long-period-grating-type sensor, and its ease of fabrication offers a low-cost alternative to current sensing applications.

  15. Coherent supercontinuum generation from 1.4 to 4 μm in a tapered fluorotellurite microstructured fiber pumped by a 1980 nm femtosecond fiber laser

    NASA Astrophysics Data System (ADS)

    Li, Nan; Wang, Fang; Yao, Chuanfei; Jia, Zhixu; Zhang, Lei; Feng, Yan; Hu, Minglie; Qin, Guanshi; Ohishi, Yasutake; Qin, Weiping

    2017-02-01

    Coherent supercontinuum light expanding from 1.4 to 4 μm is generated in a 4 cm long tapered fluorotellurite microstructured fiber (MF) pumped by a 1980 nm femtosecond fiber laser. The spectral broadening in the tapered fluorotellurite MF is caused by self-phase modulation, the Raman soliton, and red-shifted dispersive wave generation. Our results show that tapered fluorotellurite MFs are promising nonlinear medium for generating coherent broadband mid-infrared supercontinuum light.

  16. Multiplexing of PVA-coated multimode-fiber taper humidity sensors

    NASA Astrophysics Data System (ADS)

    Wang, Xueping; Zhao, Chun-Liu; Li, Jihui; Jin, Yongxing; Ye, Manping; Jin, Shangzhong

    2013-11-01

    A simple multiplexing method for relative humidity (RH) sensors based on multimode-fiber tapers (MFTs) is proposed and demonstrated. By cascading a polyvinyl alcohol (PVA) coated MFT with every channel of an Arrayed-Waveguide Grating (AWG), multipoint RH measurement is achieved. Experimental results show that the proposed multipoint RH sensor system works well. The output power for every sensor head is almost linearly increased with the RH, and the average sensitivity of the proposed sensor is about 0.23 nW/%RH within the measurement range of 35%RH-90%RH with the taper waist diameter of ˜22 μm.

  17. Evanescent wave absorption sensor based on tapered multimode fiber coated with monolayer graphene film

    NASA Astrophysics Data System (ADS)

    Qiu, Hengwei; Gao, Saisai; Chen, Peixi; Li, Zhen; Liu, Xiaoyun; Zhang, Chao; Xu, Yuanyuan; Jiang, Shouzhen; Yang, Cheng; Huo, Yanyan; Yue, Weiwei

    2016-05-01

    An evanescent wave absorption (EWA) sensor based on tapered multimode fiber (TMMF) coated with monolayer graphene film for the detection of double-stranded DNA (DS-DNA) is investigated in this work. The TMMF is a silica multimode fiber (nominally at 62.5 μm), which was tapered to symmetric taper with waist diameters of ~30 μm and total length of ~3 mm. Monolayer graphene film was grown on a copper foil via chemical vapor deposition (CVD) technology and transferred onto skinless tapered fiber core via dry transfer technology. All the components of the sensor are coupled together by fusion splicer in order to eliminate the external disturbance. DS-DNA is created by the assembly of two relatively complemented oligonucleotides. The measurements are obtained by using a spectrometer in the optical wavelength range of 400-900 nm. With the increase of DS-DNA concentration, the output light intensity (OPLI) arisen an obvious attenuation. Importantly, the absorbance (A) and the DS-DNA concentrations shown a reasonable linear variation in a wide range of 5-400 μM. Through a series of comparison, the accuracy of TMMF sensor with graphene (G-TMMF) is much better than that without graphene (TMMF), which can be attributed to the molecular enrichment of graphene by π-π stacking.

  18. Tapered TeX glass optical fibers for remote IR spectroscopic analysis

    NASA Astrophysics Data System (ADS)

    Le Foulgoc, Karine; Le Neindre, Lydia; Zhang, Xhang H.; Lucas, Jacques

    1996-12-01

    Infrared TeX fibers operating in a wide wavelength region have various potential uses in the short distance area such as laser power delivery, remote temperature monitoring and chemical analysis. TeX glass fibers with a minimum attenuation of 0.5 dB/m in the 7 - 10 micrometer range have been obtained. A plastic coating protects these fibers from external environment and improves their mechanical properties. Remote spectroscopy using mono-index fiber is one of the most promising applications. This new technology allows the identification and in situ analysis of many substances such as oils and fertilizers, which have their fingerprint in the 2 - 13 micrometer domain. The detection efficiency using evanescent wave absorption has been studied as a function of the fiber's diameter. It is found that the sensitivity increases very rapidly when the fibers' diameter decreases. The possibility of detecting very low concentrations has been tested by using TeX tapered fibers.

  19. Performance evaluation of four-wave mixing in a graphene-covered tapered fiber

    NASA Astrophysics Data System (ADS)

    Jin, Qiang; Lu, Jiamei; Li, Xibin; Yan, Qiang; Gao, Qianyu; Gao, Shiming

    2016-07-01

    Four-wave mixing in a monolayer graphene-covered tapered fiber is theoretically analyzed by taking into account the influence of the graphene layer on the light-field distribution. A figure-of-merit (FOM) coefficient, considering both the high nonlinearity and the heavy absorption, is redefined to evaluate nonlinear performance. The fiber diameter and length are optimized to acquire a higher FOM. Using such a graphene-covered tapered fiber with an optimal diameter of 0.736 μm, a maximum conversion efficiency of -38.07 dB is numerically obtained for the 1.55 μm pump when the graphene length is 34.4 μm and the peak pump power is 10 W. Moreover, a 3 dB bandwidth as broad as 430 nm can be realized in the 1.55 μm telecommunication band.

  20. Investigation on spectral response of micro-cavity structure by symmetrical tapered fiber tips

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Li, Yang; Yan, Xiaojun; Li, Weidong

    2016-06-01

    We proposed and experimentally demonstrated a micro-cavity structure made of symmetrical tapered fiber tips. The waist of a conventional fiber taper fabricated from heating and stretching technique is symmetrically cleaved, and the aligned fiber tips with air gap constitute a Fabry-Perot micro-cavity due to the reflection at the tip facet. The spectral responses of such micro-cavity structure have been investigated both in beam propagation models and experiments. The multibeam interference in the micro-cavity and the impact of the waist diameter and cavity length on the spectral response has been successfully demonstrated. And a micro-cavity structure with 45 μm waist diameter was experimentally achieved, the measured spectra agree well with the simulation ones, indicating that the spectral response of the micro-cavity structure is contributed by both the multibeam interference and the Fabry-Perot micro-cavity.

  1. The application of tapered multi-mode fiber in laser signal simulation

    NASA Astrophysics Data System (ADS)

    Yin, Ruiguang; Guo, Hao; Liang, Weiwei; Zhang, Wenpan; Li, Hui

    2016-09-01

    According to laser signal simulation, the advantage of application of tapered multi-mode fiber on laser pulse signal transmission was analyzed. By optical system simulation, the effect on the coupling efficiency of 1.06μm laser pulse signal of different angle was analyzed. By optical experiment, the coupling efficiency and transmission mode of different incident angle and force condition were confirmed. Combining the application of simulation system, with convex lens, frosted glass and optical integrator on the outlet of fiber, the far-field energy distribution was measured. According the receiving optical system entrance pupil, the effect on the beam quality to the simulation result was analyzed. The results showed that the application of tapered multi-mode fiber on laser pulse signal simulation is feasible, and the equipment has been used in the engineering projects.

  2. Photonic crystal fiber half-taper probe based refractometer.

    PubMed

    Wang, Pengfei; Ding, Ming; Bo, Lin; Guan, Chunying; Semenova, Yuliya; Sun, Weimin; Yuan, Libo; Brambilla, Gilberto; Farrell, Gerald

    2014-04-01

    A compact single-mode photonic crystal fiber single-mode fiber tip (SPST) refractive index sensor is demonstrated in this Letter. A CO2 laser cleaving technique is utilized to provide a clean-cut fiber tip, which is then coated by a layer of gold to increase reflection. An average sensitivity of 39.1 nm/RIU and a resolvable index change of 2.56×10(-4) are obtained experimentally with a ∼3.2 μm diameter SPST. The temperature dependence of this fiber-optic sensor probe is presented. The proposed SPST refractometer is also significantly less sensitive to temperature and an experimental demonstration of this reduced sensitivity is presented in the Letter. Because of its compactness, ease of fabrication, linear response, low temperature dependency, easy connectivity to other fiberized optical components and low cost, this refractometer could find various applications in chemical and biological sensing.

  3. A highly reproducible and sensitive fiber SERS probe fabricated by direct synthesis of closely packed AgNPs on the silanized fiber taper.

    PubMed

    Cao, Jie; Zhao, Di; Mao, Qinghe

    2017-01-27

    A surface-enhanced Raman scattering (SERS) tapered fiber probe has been developed by using a chemically-etched tapered fiber tip and silanization of the surface of the fiber taper, followed by the hydrothermal growth of silver nanoparticles (AgNPs) on the silanized fiber taper. 4-Aminothiophenol (4-ATP) was selected as the target analyte to study the SERS responses of the prepared fiber SERS probe in an optrode remote detection mode. The experimental results show that the prepared fiber probe exhibited the ability to detect the 4-ATP molecule at a concentration as low as 10(-9) M and good reproducibility with the relative standard deviation (RSD) values being less than 9.1% for the strongest Raman peak. This work gives a novel and reliable way to realize a fiber SERS probe with high sensitivity, long-term stability, good reproducibility, and superior recyclability, exhibiting potential in SERS-based in situ detection application.

  4. Tapered and linearly chirped fiber Bragg gratings with co-directional and counter-directional resultant chirps

    NASA Astrophysics Data System (ADS)

    Osuch, Tomasz

    2016-05-01

    A method of spectral width tailoring of tapered fiber Bragg gratings is theoretically analyzed and experimentally verified. This concept is based on inscription grating structures in which synthesis of chirps comes from both taper profile and a linearly chirped phase mask used for grating inscription. It is shown that under UV exposure and depending on the orientation of the optical fiber taper relative to the variable-pitch phase mask, tapered and linearly chirped fiber Bragg gratings (TCFBG) with resultant co-directional or counter-directional chirps are achieved. Thus, both effects, those of reduction and enhancement of the grating chirp, as well as their influence on the grating spectral response, are presented. In particular, using the above approach TCFBG with significantly narrowed spectral width are shown. Moreover, fused tapered chirped FBG with relatively large waist diameter are shown having broad spectrum, something that prior to now was not attainable using previously developed techniques.

  5. Tapered Optical Fiber Probe Assembled with Plasmonic Nanostructures for Surface-Enhanced Raman Scattering Application.

    PubMed

    Huang, Zhulin; Lei, Xing; Liu, Ye; Wang, Zhiwei; Wang, Xiujuan; Wang, Zhaoming; Mao, Qinghe; Meng, Guowen

    2015-08-12

    Optical fiber-Raman devices integrated with plasmonic nanostructures have promising potentials for in situ probing remote liquid samples and biological samples. In this system, the fiber probe is required to simultaneously demonstrate stable surface enhanced Raman scattering (SERS) signals and high sensitivity toward the target species. Here we demonstrate a generic approach to integrate presynthesized plasmonic nanostructures with tapered fiber probes that are prepared by a dipping-etching method, through reversed electrostatic attraction between the silane couple agent modified silica fiber probe and the nanostructures. Using this approach, both negatively and positively charged plasmonic nanostructures with various morphologies (such as Au nanosphere, Ag nanocube, Au nanorod, Au@Ag core-shell nanorod) can be stably assembled on the tapered silica fiber probes. Attributed to the electrostatic force between the plasmonic units and the fiber surface, the nanostructures do not disperse in liquid samples easily, making the relative standard deviation of SERS signals as low as 2% in analyte solution. Importantly, the detection sensitivity of the system can be optimized by adjusting the cone angle (from 3.6° to 22°) and the morphology of nanostructures assembled on the fiber. Thus, the nanostructures-sensitized optical fiber-Raman probes show great potentials in the applications of SERS-based environmental detection of liquid samples.

  6. The tension sensor of Photonic Crystal Fiber based on core-offset splicing and waist-enlarged fiber taper

    NASA Astrophysics Data System (ADS)

    Fu, Guangwei; Li, Qifeng; Li, Yunpu; Yang, Jiandong; Fu, Xinghu; Bi, Weihong; Li, Yanjun

    2016-10-01

    A tension sensor of Photonic Crystal Fiber(PCF) is presented based on core-offset splicing and waist-enlarged fiber taper. The tension response characteristics of the sensor are studied experimentally. To analyzing the modal interference, many samples with different PCF lengths between the two splicing areas, different core-offset distances and different waist-enlarged fiber taper diameters are fabricated and tested. When the tension range is 0 to 4000μɛ, the results show that the spectrum is blue shift with the increasing of the axial tension. The sensitivity is-2.1 pm/μɛ. The experimental results show that the tension sensitivity can be not influenced by the PCF lengths, the core-offset distances.The waist-enlarged fiber taper diameters and the tension sensor is very sensitive to axial tension and the relationship between the wavelength shift and tension is linearity. To determine the number of the interfering modes, the transmission spectra of these sensor is transformed by the fast fourier transform (FFT) method. There are several peaks in the spatial frequency spectra at these sensors. Only one cladding mode is dominantly excited, while the other cladding modes are weak. The spatial frequency is proportional to the differential mode group index. Compared with the traditional fiber sensor, this sensor has some advantages including the easily fabricated, simple structure and high sensitivity. It can be used in industrial production, building monitoring, aerospace and other fields.

  7. Nonadiabatic tapered optical fiber sensor for measurement of antimicrobial activity of silver nanoparticles against Escherichia coli.

    PubMed

    Zibaii, Mohammad Ismail; Latifi, Hamid; Saeedian, Zahra; Chenari, Zinab

    2014-06-05

    Silver nanoparticles (SNPs) exhibit antibacterial properties via bacterial inactivation and growth inhibition but the mechanism is not yet completely understood. In this study a label free and rapid detection method for study of antimicrobial activity of the SNP against Escherichia coli (E. coli K-12) is investigated using a nonadiabtic tapered fiber optic (NATOF) biosensor. The results show that SNPs interact with bacteria either by anchoring to or penetrating into the bacterial cell layer. These mechanism changes the refractive index (RI) of the tapered region, which in turn lead to the changes in the optical characteristics of the tapered fiber and output signals. With similar conditions for bacteria, the inhibition rate of the E. coli growth was measured by colony counting method as an experimental control and the results were compared with those obtained from the fiber sensor measurements. For SNP concentrations ranging from 0 to 50 μg ml(-1) the inhibition rates of the E. coli growth were measured to be from 1.27 h(-1) to -0.69 h(-1) and from -3.00×10(-3) h(-1) to -1.98×10(-2) h(-1) for colony counting and optical fiber biosensor, respectively. The results demonstrate the potential of the proposed NATOF biosensor as a label free and rapid sensing platform for understanding the mechanism of antibacterial effects of SNPs.

  8. Charge-coupled device/fiber optic taper array x-ray detector for protein crystallography

    SciTech Connect

    Naday, I.; Ross, S.; Westbrook, E.M.; Zentai, G.

    1998-04-01

    A large area charge-coupled device (CCD) based fiber optic taper array detector (APS-1) is installed at the insertion-device beamline of the Structural Biology Center at the Argonne Advanced Photon Source x-ray synchrotron. The detector is used in protein crystallography diffraction experiments, where the objective is to measure the position and intensity of x-ray Bragg peaks in diffraction images. Large imaging area, very high spatial resolution, high x-ray sensitivity, good detective quantum efficiency, low noise, wide dynamic range, excellent stability and short readout time are all fundamental requirements in this application. The APS-1 detector converts the 2-D x-ray patterns to visible light images by a thin layer of x-ray sensitive phosphor. The phosphor coating is directly deposited on the large ends of nine fiber optic tapers arranged in a 3{times}3 array. Nine, thermoelectrically cooled 1024{times}1024pixel CCDs image the patterns, demagnified by the tapers. After geometrical and uniformity corrections, the nine areas give a continuous image of the detector face with virtually no gaps between the individual tapers. The 18 parallel analog signal-processing channels and analog-to-digital converters ensure short readout time and low readout noise. We discuss the design and measured performance of the detector. {copyright} {ital 1998 Society of Photo-Optical Instrumentation Engineers.}{ital Key words:} charge-coupled device; fiber optic taper; x-ray diffraction; crystallography; imaging detector. {copyright} {ital 1998} {ital Society of Photo-Optical Instrumentation Engineers}

  9. Compact bending sensor based on a fiber Bragg grating in an abrupt biconical taper.

    PubMed

    Cui, Wei; Si, Jinhai; Chen, Tao; Hou, Xun

    2015-05-04

    We propose and experimentally demonstrate a compact bending sensor. The head of the sensor is only 0.8 mm in length, and consists of an abrupt biconical fiber taper formed using a conventional fusion splicer, in which a fiber Bragg grating (FBG) is inscribed using a femtosecond laser. The biconical taper incorporating the FBG can couple light from the cladding to the backward-propagating core mode, which realizes an interferometer in reflection-mode. Bending of the structure can be detected from the contrast change of interference fringes. A configuration to measure curvature is investigated to demonstrate the sensing characteristics. The temperature cross-sensitivity of the sensor is studied, and the results demonstrate that it is insensitive to temperature.

  10. Single-mode tapered optical fiber loop immunosensor II: assay of anti-cholera toxin immunoglobulins

    NASA Astrophysics Data System (ADS)

    Marks, Robert S.; Hale, Zoe M.; Levine, Myron M.; Lowe, C. R.; Payne, Frank P.

    1994-07-01

    An evanescent wave immunoassay for cholera antitoxin immunoglobulins was performed using a single mode tapered optical fiber loop sensor. The transducer was silanized with 3- glycidoxypropyltrimethoxysilane and chemically modified to link covalently either cholera toxin B subunit or a synthetic peptide derived from it, CTP3. The sensor was exposed to seral fluids, obtained from human volunteers having been exposed to live virulent Vibrio cholerae 01 and shown to produce rice-water stools. Other toxins of interest, such as Clostridium botulinum toxin A, have been tested on similar systems. The bound unlabelled immunoglobulins were then exposed to a mixture of FITC-anti-IgG and TRITC-anti-IgA, without requirement for a separation step. The emanating fluorescent emissions of fluorescein and rhodamine, excited by the input laser light, were coupled back into the guided mode of the tapered fiber, and used to determine the concentrations of the complementary antigens.

  11. An in vitro analysis of separation of multi-use ProTaper Universal and ProTaper Next instruments in extracted mandibular molar teeth.

    PubMed

    Ertas, Huseyin; Capar, Ismail Davut

    2015-01-01

    This study investigated the separation incidence of reused ProTaper Universal and ProTaper Next rotary instruments and identified the location of separated fragments. The root canals of extracted human mandibular molars were prepared with 10 assorted sets of ProTaper Universal and ProTaper Next instruments. After each preparation, instrument sets were autoclaved. This arrangement was repeated until an instrument fractured. The number of prepared teeth until fracture occurred was recorded for each instrument set. Teeth in which the instruments fractured were analyzed to determine the separation grade, apical relation, and coronal position. Fracture surfaces of the instruments were examined with scanning electron microscope. ProTaper Universal instruments fractured after application to a mean of 7.3 teeth, and ProTaper Next instruments after application to a mean of 5.7 teeth (p > 0.05). In the ProTaper Universal and ProTaper Next groups, F2 and X1 were the most commonly fractured instruments, respectively. Torsional and cyclic failures were evenly distributed in both the groups. The mean lengths of the fractured fragments of the instruments showed no statistically significant difference. The distance between the tip of the fractured instruments and apical constriction was similar (p > 0.05). However, the mean distance between the root canal orifice and coronal part of the fractured instrument was shorter in the ProTaper Next group (p < 0.05). The life span of ProTaper Universal and ProTaper Next instruments was the same for preparation of mandibular molar teeth. None of the instruments were fractured in the first usage.

  12. High energy supercontinuum sources using tapered photonic crystal fibers for multispectral photoacoustic microscopy.

    PubMed

    Bondu, Magalie; Brooks, Christopher; Jakobsen, Christian; Oakes, Keith; Moselund, Peter Morten; Leick, Lasse; Bang, Ole; Podoleanu, Adrian

    2016-06-01

    We demonstrate a record bandwidth high energy supercontinuum source suitable for multispectral photoacoustic microscopy. The source has more than 150  nJ/10  nm bandwidth over a spectral range of 500 to 1600 nm. This performance is achieved using a carefully designed fiber taper with large-core input for improved power handling and small-core output that provides the desired spectral range of the supercontinuum source.

  13. Simultaneous measurement of strain, temperature and refractive index based on multimode interference, fiber tapering and fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Oliveira, Ricardo; Osório, Jonas H.; Aristilde, Stenio; Bilro, Lúcia; Nogueira, Rogerio N.; Cordeiro, Cristiano M. B.

    2016-07-01

    We report the development of an optical fiber sensor capable of simultaneously measuring strain, temperature and refractive index. The sensor is based on the combination of two fiber Bragg gratings written in a standard single-mode fiber, one in an untapered region and another in a tapered region, spliced to a no-core fiber. The possibility of simultaneously measuring three parameters relies on the different sensitivity responses of each part of the sensor. The results have shown the possibility of measuring three parameters simultaneously with a resolution of 3.77 μɛ, 1.36 °C and 5  ×  10-4, respectively for strain, temperature and refractive index. On top of the multiparameter ability, the simple production and combination of all the parts involved on this optical-fiber-based sensor is an attractive feature for several sensing applications.

  14. Enlarged-taper tailored Fiber Bragg grating with polyvinyl alcohol coating for humidity sensing

    NASA Astrophysics Data System (ADS)

    Liang, Yanhong; Yan, Guofeng; He, Sailing

    2015-08-01

    In this paper, a novel optical fiber sensor based on an enlarged-taper tailored fiber Bragg grating (FBG) is proposed and experimentally demonstrated for the measurement of relative humidity. The enlarged-taper works as a multifunctional joint that not only excites cladding modes but also recouples the cladding modes reflected by the FBG back into the leading single mode fiber. Due to the fact that cladding modes have a strong evanescent field penetrating into the ambient medium, the intensity of the reflected cladding modes is greatly influenced by the refractive index (RI) of the ambient medium. Polyvinyl alcohol (PVA) film is plated on the fiber surface by dip-coating technique, as a humidity-to-refractive index transducer, whose RI variance from 1.49 to 1.34 when the ambient humidity increases from 20%RH to 95%RH. The relative humidity response of the sensing structure is investigated in our home-made humidity chamber with a commercial hygrometer. By monitoring the intensity of the reflected cladding modes, the RH variance can be demodulated. Experimental results show that RH sensitivity depends on the RH value, and a sensitivity up to 1.2 dB/%RH can be achieved within the RH range of 30-90%. A fast and reversible time response has also been investigated. Such a probe-type and reusable fiber-optic RH sensor is a very promising technology for biochemical sensing applications, e.g., breath analysis, chemical reaction monitoring.

  15. Single mode tapered fiber-optic interferometer based refractive index sensor and its application to protein sensing.

    PubMed

    Yadav, T K; Narayanaswamy, R; Abu Bakar, M H; Kamil, Y Mustapha; Mahdi, M A

    2014-09-22

    We demonstrate refractive index sensors based on single mode tapered fiber and its application as a biosensor. We utilize this tapered fiber optic biosensor, operating at 1550 nm, for the detection of protein (gelatin) concentration in water. The sensor is based on the spectroscopy of mode coupling based on core modes-fiber cladding modes excited by the fundamental core mode of an optical fiber when it transitions into tapered regions from untapered regions. The changes are determined from the wavelength shift of the transmission spectrum. The proposed fiber sensor has sensitivity of refractive index around 1500 nm/RIU and for protein concentration detection, its highest sensitivity is 2.42141 nm/%W/V.

  16. Wide-field lensless fluorescent microscopy using a tapered fiber-optic faceplate on a chip.

    PubMed

    Coskun, Ahmet F; Sencan, Ikbal; Su, Ting-Wei; Ozcan, Aydogan

    2011-09-07

    We demonstrate lensless fluorescent microscopy over a large field-of-view of ~60 mm(2) with a spatial resolution of <4 µm. In this on-chip fluorescent imaging modality, the samples are placed on a fiber-optic faceplate that is tapered such that the density of the fiber-optic waveguides on the top facet is >5 fold larger than the bottom one. Placed on this tapered faceplate, the fluorescent samples are pumped from the side through a glass hemisphere interface. After excitation of the samples, the pump light is rejected through total internal reflection that occurs at the bottom facet of the sample substrate. The fluorescent emission from the sample is then collected by the smaller end of the tapered faceplate and is delivered to an opto-electronic sensor-array to be digitally sampled. Using a compressive sampling algorithm, we decode these raw lensfree images to validate the resolution (<4 µm) of this on-chip fluorescent imaging platform using microparticles as well as labeled Giardia muris cysts. This wide-field lensfree fluorescent microscopy platform, being compact and high-throughput, might provide a valuable tool especially for cytometry, rare cell analysis (involving large area microfluidic systems) as well as for microarray imaging applications.

  17. Numerical analysis of double chirp effect in tapered and linearly chirped fiber Bragg gratings.

    PubMed

    Markowski, Konrad; Jedrzejewski, Kazimierz; Osuch, Tomasz

    2016-06-10

    In this paper, a theoretical analysis of recently developed tapered chirped fiber Bragg gratings (TCFBG) written in co-directional and counter-directional configurations is presented. In particular, the effects of the synthesis of chirps resulting from both a fused taper profile and a linearly chirped fringe pattern of the induced refractive index changes within the fiber core are extensively examined. For this purpose, a numerical model based on the transfer matrix method (TMM) and the coupled mode theory (CMT) was developed for such a grating. The impact of TCFBG parameters, such as grating length and steepness of the taper transition, as well as the effect of the fringe pattern chirp rate on the spectral properties of the resulting gratings, are presented. Results show that, by using the appropriate design process, TCFBGs with reduced or enhanced resulting chirp, and thus with widely tailored spectral responses, can be easily achieved. In turn, it reveals a great potential application of such structures. The presented numerical approach provides an excellent tool for TCFBG design.

  18. S-tapered photonic crystal fiber interferometers for refractive index sensing

    NASA Astrophysics Data System (ADS)

    Shi, Feifei; Wu, Yun; Wang, Jinzhong; Zhao, Liancheng; Shi, Huizhong

    2013-03-01

    An experimental investigation on an S-tapered photonic crystal fiber interferometer is presented. The whole fabrication process was carried out using a standard splicing machine. The interferometer shows a compact and stable structure with a waist diameter of 110 μm, taper length of 280 μm, and axial offset of 40 μm. The transmission spectra indicated that it is highly sensitive to the surrounding refractive index (RI) and insensitive to temperature. Resolutions of 3.3×10-4 and 8.0×10-5 RI units were achieved in the 1.33 to 1.38 and 1.38 to 1.44 range, respectively. Furthermore, its temperature dependence was only 4 pm/°C.

  19. Biconically tapered fiber optic dip probe for rapid label-free immunoassays

    NASA Astrophysics Data System (ADS)

    Miller, John; Castaneda, Angelica; Lee, Kun Ho; Sanchez, Martin; Murinda, Shelton; Lin, Wei-Jen; Salik, Ertan

    2014-02-01

    We report U-shaped biconically tapered optical fibers (BTOF) as dip probes for label-free immunoassays. The tapered regions of the sensors were functionalized by immobilization of immunoglobulin-G (Ig-G) and tested for detection of anti-IgG at concentrations of 0.5, 5.0, and 50 μg/mL. Antibody-antigen reaction creates a biological nanolayer modifying the waveguide structure leading to a change in the sensor signal, which allows real-time monitoring. The kinetics of the antibody (mouse Ig-G) -antigen (rabbit anti-mouse IgG) reactions was studied. The limit of detection for the sensor was estimated to be less than 0.5 μg/mL with low temperature sensitivity. Utilization of the rate of the sensor peak shift within the first few minutes of antibody-antigen reaction is proposed as a rapid detection method.

  20. Coupling Single-Mode Fiber to Uniform and Symmetrically Tapered Thin-Film Waveguide Structures Using Gadolinium Gallium Garnet

    NASA Technical Reports Server (NTRS)

    Gadi, Jagannath; Yalamanchili, Raj; Shahid, Mohammad

    1995-01-01

    The need for high efficiency components has grown significantly due to the expanding role of fiber optic communications for various applications. Integrated optics is in a state of metamorphosis and there are many problems awaiting solutions. One of the main problems being the lack of a simple and efficient method of coupling single-mode fibers to thin-film devices for integrated optics. In this paper, optical coupling between a single-mode fiber and a uniform and tapered thin-film waveguide is theoretically modeled and analyzed. A novel tapered structure presented in this paper is shown to produce perfect match for power transfer.

  1. C- and L-band tunable fiber ring laser using a two-taper Mach-Zehnder interferometer filter.

    PubMed

    Wang, Xiaozhen; Li, Yi; Bao, Xiaoyi

    2010-10-15

    A stable C- and L-band tunable fiber ring laser, using a two-taper Mach-Zehnder interferometer (MZI) as a filter, is proposed and demonstrated experimentally. One of the two taper waists is mechanically bent to tune the laser wavelength. Being amplified by an L-band erbium-doped fiber amplifier and an erbium-doped fiber, respectively, the fiber ring laser has a full L-band (1564-1605nm) and C-band (1550-1565nm) tuning range with a side-mode suppression ratio as high as 50dB. The laser linewidth and the minimum tuning step are related to the MZI's cavity length. It was also found that thermal annealing relieved the internal stresses of the tapers and greatly improved the laser performance.

  2. Four-wave mixing instabilities in photonic-crystal and tapered fibers.

    PubMed

    Biancalana, F; Skryabin, D V; Russell, P St J

    2003-10-01

    Four-wave mixing instabilities are theoretically studied for continuous wave propagation in ultrasmall core photonic-crystal and tapered fibers. The waveguide, or geometrical, contribution to the overall dispersion of these structures is much stronger than in conventional fibers. This leads to the appearance of unstable frequency bands that are qualitatively and quantitatively different from those seen in conventional fibers. The four-wave mixing theory developed here is based on the full wave equation, which allows rigorous study of the unstable bands even when the detunings are of the order of the pump frequency itself. Solutions obtained using the generalized nonlinear Schrödinger equation, which is an approximate version of the full wave equation, reveal that it suffers from several deficiencies when used to describe four-wave mixing processes.

  3. All-fiber dual wavelength passive Q-switched fiber laser using a dispersion-decreasing taper fiber in a nonlinear loop mirror.

    PubMed

    Ahmad, Harith; Dernaika, Mohamad; Harun, Sulaiman Wadi

    2014-09-22

    This paper describes a proposal and successful demonstration of a dual wavelength all-fiber passively Q-switched erbium-doped fiber ring laser. The Q-switch operation was realized by using a nonlinear loop mirror that incorporated an unbalanced dispersion-decreasing taper fiber to act as a saturable absorber without additional elements. This setup enabled a fiber ring laser to achieve a performance of 48.7 kHz repetition rate with pulse duration of around 3.2 μs and approximate pulse energy of 20 nJ.

  4. Taking a look at the calibration of a CCD detector with a fiber-optic taper

    DOE PAGES

    Alkire, R. W.; Rotella, F. J.; Duke, Norma E. C.; ...

    2016-02-16

    At the Structural Biology Center beamline 19BM, located at the Advanced Photon Source, the operational characteristics of the equipment are routinely checked to ensure they are in proper working order. After performing a partial flat-field calibration for the ADSC Quantum 210r CCD detector, it was confirmed that the detector operates within specifications. However, as a secondary check it was decided to scan a single reflection across one-half of a detector module to validate the accuracy of the calibration. The intensities from this single reflection varied by more than 30% from the module center to the corner of the module. Redistributionmore » of light within bent fibers of the fiber-optic taper was identified to be a source of this variation. As a result, the degree to which the diffraction intensities are corrected to account for characteristics of the fiber-optic tapers depends primarily upon the experimental strategy of data collection, approximations made by the data processing software during scaling, and crystal symmetry.« less

  5. Taking a look at the calibration of a CCD detector with a fiber-optic taper

    PubMed Central

    Alkire, R. W.; Rotella, F. J.; Duke, N. E. C.; Otwinowski, Zbyszek; Borek, Dominika

    2016-01-01

    At the Structural Biology Center beamline 19BM, located at the Advanced Photon Source, the operational characteristics of the equipment are routinely checked to ensure they are in proper working order. After performing a partial flat-field calibration for the ADSC Quantum 210r CCD detector, it was confirmed that the detector operates within specifications. However, as a secondary check it was decided to scan a single reflection across one-half of a detector module to validate the accuracy of the calibration. The intensities from this single reflection varied by more than 30% from the module center to the corner of the module. Redistribution of light within bent fibers of the fiber-optic taper was identified to be a source of this variation. The degree to which the diffraction intensities are corrected to account for characteristics of the fiber-optic tapers depends primarily upon the experimental strategy of data collection, approximations made by the data processing software during scaling, and crystal symmetry. PMID:27047303

  6. Taking a look at the calibration of a CCD detector with a fiber-optic taper

    SciTech Connect

    Alkire, R. W.; Rotella, F. J.; Duke, Norma E. C.; Otwinowski, Zbyszek; Borek, Dominika M.

    2016-02-16

    At the Structural Biology Center beamline 19BM, located at the Advanced Photon Source, the operational characteristics of the equipment are routinely checked to ensure they are in proper working order. After performing a partial flat-field calibration for the ADSC Quantum 210r CCD detector, it was confirmed that the detector operates within specifications. However, as a secondary check it was decided to scan a single reflection across one-half of a detector module to validate the accuracy of the calibration. The intensities from this single reflection varied by more than 30% from the module center to the corner of the module. Redistribution of light within bent fibers of the fiber-optic taper was identified to be a source of this variation. As a result, the degree to which the diffraction intensities are corrected to account for characteristics of the fiber-optic tapers depends primarily upon the experimental strategy of data collection, approximations made by the data processing software during scaling, and crystal symmetry.

  7. Modal demultiplexing properties of tapered and nanostructured optical fibers for in vivo optogenetic control of neural activity.

    PubMed

    Pisanello, Marco; Della Patria, Andrea; Sileo, Leonardo; Sabatini, Bernardo L; De Vittorio, Massimo; Pisanello, Ferruccio

    2015-10-01

    Optogenetic approaches to manipulate neural activity have revolutionized the ability of neuroscientists to uncover the functional connectivity underlying brain function. At the same time, the increasing complexity of in vivo optogenetic experiments has increased the demand for new techniques to precisely deliver light into the brain, in particular to illuminate selected portions of the neural tissue. Tapered and nanopatterned gold-coated optical fibers were recently proposed as minimally invasive multipoint light delivery devices, allowing for site-selective optogenetic stimulation in the mammalian brain [Pisanello , Neuron82, 1245 (2014)]. Here we demonstrate that the working principle behind these devices is based on the mode-selective photonic properties of the fiber taper. Using analytical and ray tracing models we model the finite conductance of the metal coating, and show that single or multiple optical windows located at specific taper sections can outcouple only specific subsets of guided modes injected into the fiber.

  8. Near-field fluorescence thermometry using highly efficient triple-tapered near-field optical fiber probe

    NASA Astrophysics Data System (ADS)

    Fujii, T.; Taguchi, Y.; Saiki, T.; Nagasaka, Y.

    2012-12-01

    A novel local temperature measurement method using fluorescence near-field optics thermal nanoscopy (Fluor-NOTN) has been developed. Fluor-NOTN enables nanoscale temperature measurement in situ by detecting the temperature-dependent fluorescence lifetime of CdSe quantum dots (QDs). In this paper, we report a novel triple-tapered near-field optical fiber probe that can increase the temperature measurement sensitivity of Fluor-NOTN. The performance of the proposed probe was numerically evaluated by the finite difference time domain method. Due to improvements in both the throughput and collection efficiency of near-field light, the sensitivity of the proposed probe was 1.9 times greater than that of typical double-tapered probe. The proposed shape of the triple-tapered core was successfully fabricated utilizing a geometrical model. The detected signal intensity of dried layers of QDs was greater by more than two orders than that of auto-fluorescence from the fiber core. In addition, the near-field fluorescence lifetime of the QDs and its temperature dependence were successfully measured by the fabricated triple-tapered near-field optical fiber probe. These measurement results verified the capability of the proposed triple-tapered near-field optical fiber probe to improve the collection efficiency of near-field fluorescence.

  9. Sub-nanometer tuning of mode-locked pulse by mechanical strain on tapered fiber

    NASA Astrophysics Data System (ADS)

    Ahmad, Harith; Faruki, Md Jahid; Tiu, Zian Cheak; Thambiratnam, K.

    2017-03-01

    A tunable mode-locked fiber laser based on the non-linear polarization rotation (NPR) technique is proposed and demonstrated. A passively generated mode-locked output is obtained with a repetition rate of about 70 ns and an average output power of 0.7 mW, as well as a laser efficiency of 0.53%. The mode-locked pulses can be tuned over a span of 4.4 nm, from 1560.6 nm to 1556.2, corresponding to a stretching of the tapered fiber from 0 to 100 μm in 10 μm increments. The pulses have an average signal-to-noise ratio of about 41 dB in the frequency domain, indicating a highly stable mode-locked output. The system can repeat and reverse the generation of these pulses, a crucial criterion of many communications and sensing applications.

  10. Transmission degradation and preservation for tapered optical fibers in rubidium vapor.

    PubMed

    Lai, Meimei; Franson, James D; Pittman, Todd B

    2013-04-20

    The use of subwavelength diameter tapered optical fibers (TOFs) in warm rubidium vapor has recently been identified as a promising system for realizing ultralow-power nonlinear optical effects. However, at the relatively high atomic densities needed for many of these experiments, rubidium atoms accumulating on the TOF surface can cause a significant loss of overall transmission through the fiber. Here we report direct measurements of the time scale associated with this transmission degradation for various rubidium density conditions. Transmission is affected almost immediately after the introduction of rubidium vapor into the system, and declines rapidly as the density is increased. More significantly, we show how a heating element designed to raise the TOF temperature can be used to reduce this transmission loss and dramatically extend the effective TOF transmission lifetime.

  11. Tapered fiber coupling of single photons emitted by a deterministically positioned single nitrogen vacancy center

    SciTech Connect

    Liebermeister, Lars Petersen, Fabian; Münchow, Asmus v.; Burchardt, Daniel; Hermelbracht, Juliane; Tashima, Toshiyuki; Schell, Andreas W.; Benson, Oliver; Meinhardt, Thomas; Krueger, Anke; Stiebeiner, Ariane; Rauschenbeutel, Arno; Weinfurter, Harald; Weber, Markus

    2014-01-20

    A diamond nano-crystal hosting a single nitrogen vacancy (NV) center is optically selected with a confocal scanning microscope and positioned deterministically onto the subwavelength-diameter waist of a tapered optical fiber (TOF) with the help of an atomic force microscope. Based on this nano-manipulation technique, we experimentally demonstrate the evanescent coupling of single fluorescence photons emitted by a single NV-center to the guided mode of the TOF. By comparing photon count rates of the fiber-guided and the free-space modes and with the help of numerical finite-difference time domain simulations, we determine a lower and upper bound for the coupling efficiency of (9.5 ± 0.6)% and (10.4 ± 0.7)%, respectively. Our results are a promising starting point for future integration of single photon sources into photonic quantum networks and applications in quantum information science.

  12. Lensless fluorescent on-chip microscopy using a fiber-optic taper.

    PubMed

    Coskun, Ahmet F; Sencan, Ikbal; Su, Ting-Wei; Ozcan, Aydogan

    2011-01-01

    We demonstrate a lensfree on-chip fluorescent microscopy platform that can image fluorescently labeled cells over ~60 mm(2) field-of-view with <4 urn spatial resolution. In this lensfree imaging system, micro-objects of interest are directly located on a tapered fiber-optic faceplate which has > 5-fold higher density of fiber-optic waveguides in its top facet compared to the bottom facet. For excitation, an incoherent light source (e.g., a simple light emitting diode--LED) is used to pump fluorescent objects through a glass hemi-sphere interface. Upon interacting with the entire sample volume, the excitation light is rejected by total internal reflection process occurring at the bottom of the sample substrate. Fluorescent emission from the objects is then collected by the smaller facet of the tapered faceplate and is delivered to a detector-array with an image magnification of ~2.4X. A compressive sampling based decoding algorithm is used for sparse signal recovery, which further increases the space-bandwidth-product of our lensfree on-chip fluorescent imager. We validated the performance of this lensfree imaging platform using fluorescent micro-particles as well as labeled water-borne parasites (e.g., Giardia Muris cysts). Such a compact and wide-field fluorescent microscopy platform could be valuable for cytometry and rare cell imaging applications as well as for micro array research.

  13. Single tapered fiber tip for simultaneous measurements of thickness, refractive index and distance to a sample.

    PubMed

    Moreno-Hernández, Carlos; Monzón-Hernández, David; Hernández-Romano, Iván; Villatoro, Joel

    2015-08-24

    We demonstrate the capability of an air cavity Fabry-Perot interferometer (FPI), built with a tapered lead-in fiber tip, to measure three parameters simultaneously, distance, group refractive index and thickness of transparent samples introduced in the cavity. Tapering the lead-in fiber enhances the light coupling back efficiency, therefore is possible to enlarge the air cavity without a significant deterioration of the fringe visibility. Fourier transformation, used to analyze the reflected optical spectrum of our FPI, simplify the calculus to determine the position, thickness and refractive index. Samples made of 7 different glasses; fused silica, BK7, BalF5, SF2, BaF51, SF15, and glass slides were used to test our FPI. Each sample was measured nine times and the results for position, thickness and refractive index showed differences of ± 0.7%, ± 0.1%, and ± 0.16% respectively. The evolution of thickness and refractive index of a block of polydimethylsiloxane (PDMS) elastomer due to temperature changes in the range of 25°C to 90°C were also measured. The coefficients of the thermal expansion and thermo-optic estimated were α = 4.71x10(-4)/°C and dn/dT = -4.66 x10(-4) RIU/°C, respectively.

  14. Spectra of spontaneous Raman scattering in taper-drawn micro/nano-fibers

    NASA Astrophysics Data System (ADS)

    Xu, Yingxin; Cui, Liang; Li, Xiaoying; Guo, Cheng; Li, Yuhang; Xu, Zhongyang; Wang, Lijun; Fang, Wei

    2016-12-01

    We study the spontaneous Raman scattering (RS) in taper-drawn micro/nano-fibers (MNFs) by employing the photon counting technique. The spectra of RS in five MNFs, which are fabricated by using different heating flames (hydrogen flame or butane flame) and with different diameters, are measured within a frequency shift range of 1435 cm-1-3200 cm-1. From the measured spectra, we observe the RS peaks originated from silica and a unique RS peak with a frequency shift of ˜2905 cm-1 (˜87.2 THz). Unlike the former ones, the latter one is not observable in conventional optical fibers. Furthermore, the unique peak becomes obvious and starts to rapidly increase with the decrease of the diameter of MNFs when the diameter is smaller than 2 μm, and the intensity of the unique peak significantly depends on the heating flame used in the fabricating process. Our investigation is useful for the entanglement generation or optical sensing using taper-drawn MNFs. Project supported by the National Natural Science Foundation of China (Grant Nos. 11304222 and 11527808) and the State Key Development Program for Basic Research of China (Grant No. 2014CB340103).

  15. Evanescent field interaction of tapered fiber with graphene oxide in generation of wide-bandwidth mode-locked pulses

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Faruki, M. J.; Razak, M. Z. A.; Tiu, Z. C.; Ismail, M. F.

    2017-02-01

    Pulses with picosecond pulse widths are highly desired for high precision laser applications. A mode-locked pulse laser utilizing evanescent field interaction of a tapered fiber with graphene oxide (GO) is demonstrated. A homemade fabrication stage was used to fabricate the tapered fiber using systematic flame brushing and a GO solution was used to coat the microfiber using optical deposition technique. Pulse trains with a pulse width of 3.46 ps, a 3 dB optical bandwidth of 11.82 nm and a repetition rate of 920 kHz were obtained. The system has substantial potential for many crucial medical, communication, bio processing, military, and industrial applications.

  16. Combining comb-filters based on tapered fibers for selective lasing performance in erbium-doped fiber lasers

    NASA Astrophysics Data System (ADS)

    Nuñez-Gomez, R. E.; Anzueto-Sanchez, G.; Martinez-Rios, A.; Basurto-Pensado, M. A.; Castrellon-Uribe, J.; Camas-Anzueto, J.

    2016-12-01

    In this work, we report a new method to make a selection between tunable and multi-wavelength switchable operation in an erbium-doped fiber laser. The selective lasing performance is based on two concatenated comb-filters built on tapered optical fibers. By properly adjusting curvature applied to the comb-filters, the lasing wavelength can be selective in two ways: continuous tuning or generating multi-wavelength laser oscillation. The laser exhibits an optical signal to noise ratio of ~30 dB and power stability below 1 dB at room temperature. The main achievement of this proposal is that the laser can be operating independently between tuning and multi-wavelength lasing with a high stability employing a reliable and low-cost comb filters.

  17. Biconically Tapered Fiber Optic Probes for Rapid Label-Free Immunoassays ǂ

    PubMed Central

    Miller, John; Castaneda, Angelica; Lee, Kun Ho; Sanchez, Martin; Ortiz, Adrian; Almaz, Ekrem; Turkoglu Almaz, Zuleyha; Murinda, Shelton; Lin, Wei-Jen; Salik, Ertan

    2015-01-01

    We report use of U-shaped biconically tapered optical fibers (BTOF) as probes for label-free immunoassays. The tapered regions of the sensors were functionalized by immobilization of immunoglobulin-G (Ig-G) and tested for detection of anti-IgG at concentrations of 50 ng/mL to 50 µg/mL. Antibody-antigen reaction creates a biological nanolayer modifying the waveguide structure leading to a change in the sensor signal, which allows real-time monitoring. The kinetics of the antibody (mouse Ig-G)-antigen (rabbit anti-mouse IgG) reactions was studied. Hydrofluoric acid treatment makes the sensitive region thinner to enhance sensitivity, which we confirmed by experiments and simulations. The limit of detection for the sensor was estimated to be less than 50 ng/mL. Utilization of the rate of the sensor peak shift within the first few minutes of the antibody-antigen reaction is proposed as a rapid protein detection method. PMID:25836359

  18. Fabrication of tapered single mode fiber by chemical etching and used as a chemical sensor based on evanescent field absorption

    NASA Astrophysics Data System (ADS)

    Gangopadhyay, Tarun K.; Halder, A.; Das, S.; Paul, M. C.; Pal, M.; Salza, M.; Gagliardi, G.

    2010-12-01

    Single mode tapered fiber (SMTF) has been fabricated with core diameter of 8 μm and reduced cladding diameter up to 11 μm by hydrofluoric acid (HF) etching technique. To obtain the required cladding diameter, the time of etching has been optimized by using different HF concentrations. The mechanism as well as kinetics path of etching reaction on standard optical fiber is discussed. This study is related to surface catalyzed dissociation of HF followed by direct reaction with adsorbate molecules and the surface silicon oxide molecules. The etched tapered fibers are then packaged on quartz substrate to use as sensor element. Finally, the etched fiber is used as an element within chemical sensor based on evanescent field absorption. In this experiment, a 419-ppm cobalt nitrate solution is used for sensing.

  19. High sensitivity of taper-based Mach-Zehnder interferometer embedded in a thinned optical fiber for refractive index sensing.

    PubMed

    Yang, J; Jiang, L; Wang, S; Li, B; Wang, M; Xiao, H; Lu, Y; Tsai, H

    2011-10-01

    A taper-based Mach-Zehnder interferometer (MZI) embedded in a thinned optical fiber is demonstrated as a highly sensitive refractive index (RI) sensor. A RI sensitivity of 2210.84 nm/RIU (refractive index unit) is obtained at the external RI of 1.40, which is ten times higher than that of normal taper- and long-period fiber grating (LPFG)-based sensors. The sensitivity can be further improved by decreasing the diameter of the thinned fiber and increasing the interferometer length of the MZI. The proposed MZIs have lower temperature sensitivities compared with normal fiber sensors, which is a desirable merit for RI sensors to reduce the cross sensitivity caused by thermal drift.

  20. High Sensitivity Refractometer Based on TiO2-Coated Adiabatic Tapered Optical Fiber via ALD Technology

    PubMed Central

    Zhu, Shan; Pang, Fufei; Huang, Sujuan; Zou, Fang; Guo, Qiang; Wen, Jianxiang; Wang, Tingyun

    2016-01-01

    Atomic layer deposition (ALD) technology is introduced to fabricate a high sensitivity refractometer based on an adiabatic tapered optical fiber. Different thicknesses of titanium dioxide (TiO2) nanofilm were coated around the tapered fiber precisely and uniformly under different deposition cycles. Attributed to the higher refractive index of the TiO2 nanofilm compared to that of silica, an asymmetric Fabry–Perot (F-P) resonator could be constructed along the fiber taper. The central wavelength of the F-P resonator could be controlled by adjusting the thickness of the TiO2 nanofilm. Such a F-P resonator is sensitive to changes in the surrounding refractive index (SRI), which is utilized to realize a high sensitivity refractometer. The refractometer developed by depositing 50.9-nm-thickness TiO2 on the tapered fiber shows SRI sensitivity as high as 7096 nm/RIU in the SRI range of 1.3373–1.3500. Due to TiO2’s advantages of high refractive index, lack of toxicity, and good biocompatibility, this refractometer is expected to have wide applications in the biochemical sensing field. PMID:27537885

  1. Analysis of the use of tapered graded-index polymer optical fibers for refractive-index Sensors.

    PubMed

    Arrue, J; Jiménez, F; Aldabaldetreku, G; Durana, G; Zubia, J; Lomer, M; Mateo, J

    2008-10-13

    The behavior of tapered graded-index polymer optical fibers is analyzed computationally for different refractive indices of the surrounding medium. This serves to clarify the main parameters affecting their possible performance as refractive-index sensors and extends an existing study of similar structures in glass fibers. The ray-tracing method is employed, its specific implementation is explained, and its results are compared with experimental ones, both from our laboratory and from the literature. The results show that the current commercial graded-index polymer optical fibers can be used to measure a large range of refractive indices with several advantages over glass fibers.

  2. Nonadiabatic tapered optical fiber sensor for measuring interaction nicotine with DNA

    NASA Astrophysics Data System (ADS)

    Zibaii, M. I.; Latifi, H.; Pourbeyram, H.; Gholami, M.; Taghipour, Z.; Saeedian, Z.; Hosseini, S. M.

    2011-05-01

    A nonadiabatic tapered optical fiber sensor was utilized for studying of bimolecular interactions including DNA-DNA and DNA-Drug interaction. This work presents a simple evanescent wave sensing system based on an interferometric approach, suitable to meet the requirements of lable-free sensor systems for detecting biomolecular interactions. We have demonstrated the measuring refractive index and the real time detection of interactions between biomolecules. Furthermore basic experiments were carried out, for detecting the hybridization of 25-mer DNA with an immobilized counterpart on the surface. The overall shift after the successful DNA hybridization was 9.5 nm. In this work, a new approach for studying DNA-drug interactions was successfully tested. Nicotine as a carcinogenic compound in cigarette smoke plays an important role in interaction with DNA. Different concentrations of nicotine were applied to observe the Longmuir interaction with DNA.

  3. SPR based cone tapered fiber optic chemical sensor for the detection of low water in ethanol

    NASA Astrophysics Data System (ADS)

    Pathak, A. K.; Bhardwaj, V.; Gangwar, R. K.; Singh, V. K.

    2016-05-01

    In this paper a cone tapered surface plasmon resonance (SPR) based chemical fiber sensor is fabricated and demonstrated for the detection of low water content in ethanol. Here the 11nm thickness of Aluminum (Al) is used to coat tip of probe to generate Plasmon wave. The output power has been found to increase linearly with water content in the range 1-10% due to the increase in refractive index (RI) of ethanolabove which, as the percentage of water increases in step of 20% it shows abrupt decrease in RI hence decrease in the output power. The compact size of sensor and its low cost fabrication makes it useful for many applications in the field of chemical and biochemical sensing.

  4. Simultaneous strain and temperature sensing using a slightly tapered optical fiber with an inner cavity.

    PubMed

    Chen, H F; Wang, D N; Wang, Y

    2015-03-21

    An ultracompact optical fiber mode interferometer capable of performing simultaneous strain and temperature sensing is demonstrated. The device is fabricated by using femtosecond laser micromachining together with fusion splicing techniques and followed by a tapering process. The transmission spectrum of the device exhibits a number of resonance wavelength dips, corresponding to different orders of cladding mode, which allow simultaneous strain and temperature sensing by monitoring the variation of selected two wavelength dips. The sensitivity achieved is -16.12 pm με(-1) and 85.95 pm °C(-1) for strain and temperature, respectively. The device has a spatially precise sensing capability owing to the small size of the inner air-cavity.

  5. Rotation and deformation of human red blood cells with light from tapered fiber probes

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoshuai; Huang, Jianbin; Li, Yuchao; Zhang, Yao; Li, Baojun

    2017-01-01

    Dynamic rotation and deformation of human red blood cells (RBCs) are extremely important to investigate the survival and mechanical features of cells, which will be of great physiological and pathological significance. Here, we report an optical approach that is capable of both rotating and deforming RBCs with light from two tapered fiber probes (TFPs). With laser beams at the wavelength of 980 nm injected into the TFPs, a single RBC was rotated around different axes while single or multiple RBCs were stretched by adjusting the points of action and magnitude of the optical forces from the TFPs. The biological safety of the approach was also discussed by taking the laser power required into account.

  6. U-shaped, double-tapered, fiber-optic sensor for effective biofilm growth monitoring

    PubMed Central

    Zhong, Nianbing; Zhao, Mingfu; Li, Yishan

    2016-01-01

    To monitor biofilm growth on polydimethylsiloxane in a photobioreactor effectively, the biofilm cells and liquids were separated and measured using a sensor with two U-shaped, double-tapered, fiber-optic probes (Sen. and Ref. probes). The probes’ Au-coated hemispherical tips enabled double-pass evanescent field absorption. The Sen. probe sensed the cells and liquids inside the biofilm. The polyimide–silica hybrid-film-coated Ref. probe separated the liquids from the biofilm cells and analyzed the liquid concentration. The biofilm structure and active biomass were also examined to confirm the effectiveness of the measurement using a simulation model. The sensor was found to effectively respond to the biofilm growth in the adsorption through exponential phases at thicknesses of 0–536 μm. PMID:26977344

  7. Rotation and deformation of human red blood cells with light from tapered fiber probes

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoshuai; Huang, Jianbin; Li, Yuchao; Zhang, Yao; Li, Baojun

    2016-08-01

    Dynamic rotation and deformation of human red blood cells (RBCs) are extremely important to investigate the survival and mechanical features of cells, which will be of great physiological and pathological significance. Here, we report an optical approach that is capable of both rotating and deforming RBCs with light from two tapered fiber probes (TFPs). With laser beams at the wavelength of 980 nm injected into the TFPs, a single RBC was rotated around different axes while single or multiple RBCs were stretched by adjusting the points of action and magnitude of the optical forces from the TFPs. The biological safety of the approach was also discussed by taking the laser power required into account.

  8. Refractive index and strain sensor made of S-tapered photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Shi, Feifei; Wu, Yun; Huang, Yuewu; Wang, Jinzhong; Liu, Lihua; Zhao, Liancheng

    2015-06-01

    An experimental investigation on an S-tapered photonic crystal fiber interferometer is presented in this paper. The sensor exhibits highly surrounding refractive index sensitive, which is 4.7 × 10-3 RIU (refractive index unit) in 1.33-1.39 and 1.45 × 10-3 RIU in 1.39-1.44 commensurable with general sensors. Attribute to the S-shape's distortion, red shifts are measured in axial strain test. In addition, insensitivity (4.3 pm/°C) in low temperature and sensitivity (22.4 pm/°C) in high temperature are confirmed by experiments. These properties combined with a simple fabrication process and a durable structure.

  9. Octave-spanning supercontinuum generation in in situ tapered As₂S₃ fiber pumped by a thulium-doped fiber laser.

    PubMed

    Rudy, Charles W; Marandi, Alireza; Vodopyanov, Konstantin L; Byer, Robert L

    2013-08-01

    We report a supercontinuum spanning well over an octave of measurable bandwidth from about 1 to 3.7 μm in a 2.1 mm long As₂S₃ fiber taper using the in situ tapering method. A sub-100-fs mode-locked thulium-doped fiber laser system with ~300 pJ of pulse energy was used as the pump source. Third-harmonic generation was observed and currently limits the pump pulse energy and achievable spectral bandwidth.

  10. High-temperature sensor based on an abrupt-taper Michelson interferometer in single-mode fiber.

    PubMed

    Xu, Le; Jiang, Lan; Wang, Sumei; Li, Benye; Lu, Yongfeng

    2013-04-01

    This study proposes a high-temperature sensor based on an abrupt fiber-taper Michelson interferometer (FTMI) in single-mode fiber fabricated by a fiber-taper machine and electric-arc discharge. The proposed FTMI is applied to measure temperature and refractive index (RI). A high temperature sensitivity of 118.6 pm/°C is obtained in the temperature range of 500°C-800°C. The wavelength variation is only -0.335 nm for the maximum attenuation peak, with the external RI changed from 1.333 to 1.3902, which is desirable for high-temperature sensing to eliminate the cross sensitivity to RI.

  11. Propagation source wavelet phase extraction using multi-taper method coherence estimation

    NASA Astrophysics Data System (ADS)

    Hariri Naghadeh, Diako; Morley, Christopher Keith

    2017-02-01

    It is possible to use statistical methods to extract the propagation source wavelet phase from seismic data without getting information from a well log. Using kurtosis as a high-order statistics can preserve the phase of the signal but it is highly sensitive to outliers. A new method is introduced here called the multi-taper method coherence estimation. Two steps are required: first, a cosine function that includes the dominant frequency and maximum amplitude of signal is chosen. Secondly, the maximum coherence in the frequency band of the signal, which shows the best phase matching between the time series is determined. To validate this new method real data sets were chosen and the extracted wavelet phases for noise free and noisy data sets were compared with data extracted from a well log. Extracted wavelets using Kurtosis were also generated for comparison, and demonstrate the improved results using the new method.

  12. A 160 W single-frequency laser based on an active tapered double-clad fiber amplifier

    NASA Astrophysics Data System (ADS)

    Trikshev, A. I.; Kurkov, A. S.; Tsvetkov, V. B.; Filatova, S. A.; Kertulla, J.; Filippov, V.; Chamorovskiy, Yu K.; Okhotnikov, O. G.

    2013-06-01

    We present a CW single-frequency laser at 1062 nm (linewidth <3 MHz) with 160 W of total output power based on a two stage fiber amplifier. A GTWave fiber is used for the first stage of the amplifier. A tapered double-clad fiber (T-DCF) is used for the second stage of the amplifier. The high output power is achieved due to the amplified spontaneous emission (ASE) filtering and increased stimulated Brillouin scattering (SBS) threshold inherent to the axially non-uniform geometry.

  13. Q-switched mode-locked erbium-doped fiber laser based on topological insulator Bi(2)Se(3) deposited fiber taper.

    PubMed

    Gao, Lei; Huang, Wei; Zhang, Jing Dong; Zhu, Tao; Zhang, Han; Zhao, Chu Jun; Zhang, Wei; Zhang, Hua

    2014-08-10

    We have demonstrated the passive Q-switching mode-locking operation in an erbium-doped fiber (EDF) laser by using topological insulator Bi(2)Se(3) deposited on fiber taper, whose damage threshold can be further increased by the large evanescent field interacting length. Due to the low saturation intensity, stable Q-switched mode-locked fiber lasers centered at 1562 nm can be generated at a pump power of 10 mW. The temporal and spectral characteristics for different pump strengths have also been investigated. To the best of our knowledge, it is the first time a Q-switched mode-locked EDF laser based on the fiber taper deposited by Bi(2)Se(3) was generated.

  14. High Efficiency Energy Extraction from a Relativistic Electron Beam in a Strongly Tapered Undulator

    SciTech Connect

    Sudar, N.; Musumeci, P.; Duris, J.; Gadjev, I.; Polyanskiy, M.; Pogorelsky, I.; Fedurin, M.; Swinson, C.; Kusche, K.; Babzien, M.; Gover, A.

    2016-10-19

    Here we present results of an experiment where, using a 200 GW CO2 laser seed, a 65 MeV electron beam was decelerated down to 35 MeV in a 54-cm-long strongly tapered helical magnetic undulator, extracting over 30% of the initial electron beam energy to coherent radiation. These results, supported by simulations of the radiation field evolution, demonstrate unparalleled electro-optical conversion efficiencies for a relativistic beam in an undulator field and represent an important step in the development of high peak and average power coherent radiation sources.

  15. High Efficiency Energy Extraction from a Relativistic Electron Beam in a Strongly Tapered Undulator

    DOE PAGES

    Sudar, N.; Musumeci, P.; Duris, J.; ...

    2016-10-19

    Here we present results of an experiment where, using a 200 GW CO2 laser seed, a 65 MeV electron beam was decelerated down to 35 MeV in a 54-cm-long strongly tapered helical magnetic undulator, extracting over 30% of the initial electron beam energy to coherent radiation. These results, supported by simulations of the radiation field evolution, demonstrate unparalleled electro-optical conversion efficiencies for a relativistic beam in an undulator field and represent an important step in the development of high peak and average power coherent radiation sources.

  16. High Efficiency Energy Extraction from a Relativistic Electron Beam in a Strongly Tapered Undulator

    NASA Astrophysics Data System (ADS)

    Sudar, N.; Musumeci, P.; Duris, J.; Gadjev, I.; Polyanskiy, M.; Pogorelsky, I.; Fedurin, M.; Swinson, C.; Kusche, K.; Babzien, M.; Gover, A.

    2016-10-01

    We present results of an experiment where, using a 200 GW CO2 laser seed, a 65 MeV electron beam was decelerated down to 35 MeV in a 54-cm-long strongly tapered helical magnetic undulator, extracting over 30% of the initial electron beam energy to coherent radiation. These results, supported by simulations of the radiation field evolution, demonstrate unparalleled electro-optical conversion efficiencies for a relativistic beam in an undulator field and represent an important step in the development of high peak and average power coherent radiation sources.

  17. Adiabatically tapered microstructured mode converter for selective excitation of the fundamental mode in a few mode fiber.

    PubMed

    Taher, Aymen Belhadj; Di Bin, Philippe; Bahloul, Faouzi; Tartaret-Josnière, Etienne; Jossent, Mathieu; Février, Sébastien; Attia, Rabah

    2016-01-25

    We propose a new technique to selectively excite the fundamental mode in a few mode fiber (FMF). This method of excitation is made from a single mode fiber (SMF) which is inserted facing the FMF into an air-silica microstructured cane before the assembly is adiabatically tapered. We study theoretically and numerically this method by calculating the effective indices of the propagated modes, their amplitudes along the taper and the adiabaticity criteria, showing the ability to achieve an excellent selective excitation of the fundamental mode in the FMF with negligible loss. We experimentally demonstrate that the proposed solution provides a successful mode conversion and allows an almost excellent fundamental mode excitation in the FMF (representing 99.8% of the total power).

  18. SERS Taper-Fiber Nanoprobe Modified by Gold Nanoparticles Wrapped with Ultrathin Alumina Film by Atomic Layer Deposition.

    PubMed

    Xu, Wenjie; Chen, Zhenyi; Chen, Na; Zhang, Heng; Liu, Shupeng; Hu, Xinmao; Wen, Jianxiang; Wang, Tingyun

    2017-02-25

    A taper-fiber SERS nanoprobe modified by gold nanoparticles (Au-NPs) with ultrathin alumina layers was fabricated and its ability to perform remote Raman detection was demonstrated. The taper-fiber nanoprobe (TFNP) with a nanoscale tip size under 80 nm was made by heated pulling combined with the chemical etching method. The Au-NPs were deposited on the TFNP surface with the electrostatic self-assembly technology, and then the TFNP was wrapped with ultrathin alumina layers by the atomic layer deposition (ALD) technique. The results told us that with the increasing thickness of the alumina film, the Raman signals decreased. With approximately 1 nm alumina film, the remote detection limit for R6G aqueous solution reached 10(-6) mol/L.

  19. SERS Taper-Fiber Nanoprobe Modified by Gold Nanoparticles Wrapped with Ultrathin Alumina Film by Atomic Layer Deposition

    PubMed Central

    Xu, Wenjie; Chen, Zhenyi; Chen, Na; Zhang, Heng; Liu, Shupeng; Hu, Xinmao; Wen, Jianxiang; Wang, Tingyun

    2017-01-01

    A taper-fiber SERS nanoprobe modified by gold nanoparticles (Au-NPs) with ultrathin alumina layers was fabricated and its ability to perform remote Raman detection was demonstrated. The taper-fiber nanoprobe (TFNP) with a nanoscale tip size under 80 nm was made by heated pulling combined with the chemical etching method. The Au-NPs were deposited on the TFNP surface with the electrostatic self-assembly technology, and then the TFNP was wrapped with ultrathin alumina layers by the atomic layer deposition (ALD) technique. The results told us that with the increasing thickness of the alumina film, the Raman signals decreased. With approximately 1 nm alumina film, the remote detection limit for R6G aqueous solution reached 10−6 mol/L. PMID:28245618

  20. Highly specific detection of IL-8 protein using combination tapered fiber-optic biosensor dip-probe

    NASA Astrophysics Data System (ADS)

    Wang, Chun-Wei; Kapoor, Rakesh

    2010-02-01

    We are reporting detection of IL-8 in a mixed protein solution, using combination tapered fiber-optic biosensor (CTFOB) dip-probe. Sandwich immunoassay was used as the detection technique. The specificity of the sensor was established by using two types of negative control probes. It is demonstrated that with the help of these CTFOB dipprobe we could successfully detect IL-8 with high specificity in protein mixture. The lowest detected concentration of IL-8 was 150 pM.

  1. Tapered Glass-Fiber Microspike: High-Q Flexural Wave Resonator and Optically Driven Knudsen Pump

    NASA Astrophysics Data System (ADS)

    Pennetta, Riccardo; Xie, Shangran; Russell, Philip St. J.

    2016-12-01

    Appropriately designed optomechanical devices are ideal for making ultra-sensitive measurements. Here we report a fused-silica microspike that supports a flexural resonance with a quality factor greater than 100 000 at room temperature in vacuum. Fashioned by tapering single-mode fiber (SMF), it is designed so that the core-guided optical mode in the SMF evolves adiabatically into the fundamental mode of the air-glass waveguide at the tip. The very narrow mechanical linewidth (20 mHz) makes it possible to measure extremely small changes in resonant frequency. In a vacuum chamber at low pressure, the weak optical absorption of the glass is sufficient to create a temperature gradient along the microspike, which causes it to act as a microscopic Knudsen pump, driving a flow of gas molecules towards the tip where the temperature is highest. The result is a circulating molecular flow within the chamber. Momentum exchange between the vibrating microspike and the flowing molecules causes an additional restoring force that can be measured as a tiny shift in the resonant frequency. The effect is strongest when the mean free path of the gas molecules is comparable with the dimensions of the vacuum chamber. The system offers a novel means of monitoring the behavior of weakly absorbing optomechanical sensors operating in vacuum.

  2. Ethanol extraction of phytosterols from corn fiber

    SciTech Connect

    Abbas, Charles; Beery, Kyle E.; Binder, Thomas P.; Rammelsberg, Anne M.

    2010-11-16

    The present invention provides a process for extracting sterols from a high solids, thermochemically hydrolyzed corn fiber using ethanol as the extractant. The process includes obtaining a corn fiber slurry having a moisture content from about 20 weight percent to about 50 weight percent solids (high solids content), thermochemically processing the corn fiber slurry having high solids content of 20 to 50% to produce a hydrolyzed corn fiber slurry, dewatering the hydrolyzed corn fiber slurry to achieve a residual corn fiber having a moisture content from about 30 to 80 weight percent solids, washing the residual corn fiber, dewatering the washed, hydrolyzed corn fiber slurry to achieve a residual corn fiber having a moisture content from about 30 to 80 weight percent solids, and extracting the residual corn fiber with ethanol and separating at least one sterol.

  3. The measurement of sucrose concentration by two-tapered all-fiber Mach-Zehnder interferometer employing different coupling structures and manufacture processes

    NASA Astrophysics Data System (ADS)

    Zhu, Yu-Sheng; Wang, Hsin-Wen; Hsu, Yi-Cheng

    2016-08-01

    The sucrose concentration measurement and characteristics of light coupling taper structure on sensitivity with various fabrication processes of taper structure for all-fiber Mach-Zehnder interferometer (AFMZI) are presented. Using fusion splicer with electrical discharge, the standard single-mode fiber is employed to be fabricated as conical coupling/decoupling taper structure. The basic two fabrication processes are designed as single fusion-stretching (SFS), multiple fusions without stretching (MF). The third advanced process is composed of SFS and multiple fusions without stretching processes, and called multiple fusions with single stretching (MFSS). Various types of coupling/decoupling taper structures were fabricated based on the three kinds of fabrication processes. The effects of geometry shape including taper waist, taper angle, and sensing length on sensing sensitivity of AFMZIs are estimated. The modifications of fiber core and cladding induced by thermal effect affect the refractive index distributions and shapes of taper structure. The effects of refractive index changes of fiber core and cladding on sensing sensitivity are also discussed. The AFMZI was tested by measuring aqueous sucrose solution of refractive index unit (RIU) from 1.333 to 1.420 RIU. The optical spectrums are measured by a spectrometer. The spectrum dip shifts and sensing sensitivity was measured and calculated, respectively. As shown in results, sensing sensitivities of AFMZIs of taper structure fabricated by MFSS and multiple fusions without stretching processing are generally higher than SFS. The reasons could be aimed on materials modification through thermal effect on blurring fiber core-cladding interface and proper taper angle of taper structure. The more homogeneous refractive index distribution on fiber core-cladding interface, the more detecting light power decoupled through core-cladding interface to interact with exterior environment and enhance the sensing sensitivity

  4. Analytical model for extracting mechanical properties of a single cell in a tapered micropipette

    NASA Astrophysics Data System (ADS)

    He, J. H.; Xu, W.; Zhu, L.

    2007-01-01

    A simple solid mechanical model has been developed to extract the mechanical properties of a single cell in a tapered micropipette. This analytical model is derived using the definition of elastic modulus and force equilibrium. Using the authors' model, an elastic modulus of 21.80±4.91Pa, a Poisson ratio of 0.46±0.03, and a friction coefficient of 0.0274±0.0077 are extracted for a neutrophil cell. The model is verified by finite element software and shows good agreement with experiments. The biophysical basis of the model and application in microfluidic channels for cancer cell research are discussed, while a comparison is made with other models.

  5. Acrylic and metal based Y-branch plastic optical fiber splitter with optical NOA63 polymer waveguide taper region

    NASA Astrophysics Data System (ADS)

    Ehsan, Abang Annuar; Shaari, Sahbudin; Rahman, Mohd Kamil Abd.

    2011-01-01

    We proposed a simple low-cost acrylic and metal-based Y-branch plastic optical fiber (POF) splitter which utilizes a low cost optical polymer glue NOA63 as the main waveguiding medium at the waveguide taper region. The device is composed of three sections: an input POF waveguide, a middle waveguide taper region and output POF waveguides. A desktop high speed CNC engraver is utilized to produce the mold inserts used for the optical devices. Short POF fibers are inserted into the engraved slots at the input and output ports. UV curable optical polymer glue NOA63 is injected into the waveguide taper region and cured. The assembling is completed when the top plate is positioned to enclose the device structure and connecting screws are secured. Both POF splitters have an average insertion loss of 7.8 dB, coupling ratio of 55: 45 and 57: 43 for the acrylic and metal-based splitters respectively. The devices have excess loss of 4.82 and 4.73 dB for the acrylic and metal-based splitters respectively.

  6. Design of mid-infrared amplifiers based on fiber taper coupling to erbium-doped microspherical resonator.

    PubMed

    Mescia, Luciano; Bia, Pietro; De Sario, Marco; Di Tommaso, Annalisa; Prudenzano, Francesco

    2012-03-26

    A dedicated 3D numerical model based on coupled mode theory and solving the rate equations has been developed to analyse, design and optimize an optical amplifier obtained by using a tapered fiber and a Er³⁺-doped chalcogenide microsphere. The simulation model takes into account the main transitions among the erbium energy levels, the amplified spontaneous emission and the most important secondary transitions pertaining to the ion-ion interactions. The taper angle of the optical fiber and the fiber-microsphere gap have been designed to efficiently inject into the microsphere both the pump and the signal beams and to improve their spatial overlapping with the rare earth doped region. In order to reduce the computational time, a detailed investigation of the amplifier performance has been carried out by changing the number of sectors in which the doped area is partitioned. The simulation results highlight that this scheme could be useful to develop high efficiency and compact mid-infrared amplifiers.

  7. Efficient blue conversion from a 1064 nm microchip laser in long photonic crystal fiber tapers for fluorescence microscopy.

    PubMed

    Kudlinski, A; Lelek, M; Barviau, B; Audry, L; Mussot, A

    2010-08-02

    Using a low-cost microchip laser and a long photonic crystal fiber taper, we report a supercontinuum source with a very efficient visible conversion, especially in the blue region (around 420 nm). About 30 % of the total average output power is located in the 350-600 nm band, which is of primary importance in a number of biophotonics applications such as flow cytometry or fluorescence imaging microscopy for instance. We successfully demonstrate the use of this visible-enhanced source for a three-color imaging of HeLa cells in wide-field microscopy.

  8. A switchable and stable single-longitudinal-mode, dual-wavelength erbium-doped fiber laser assisted by Rayleigh backscattering in tapered fiber

    SciTech Connect

    Gu, Jian; Yang, Yanfu Zhang, Jianyu; Wang, Xiaorui; Yuan, Yijun; Yao, Yong; Liu, Meng

    2015-09-14

    We have proposed and demonstrated a novel switchable single-longitudinal-mode (SLM), dual-wavelength erbium-doped fiber laser (DWEDFL) assisted by Rayleigh backscattering (RBS) in a tapered fiber in a ring laser configuration. The RBS feedback in a tapered fiber is a key mechanism as linewidth narrowing for laser output. A compound laser cavity ensured that the EDFL operated in the SLM state and a saturable absorber (SA) is employed to form a gain grating for both filtering and improving wavelength stability. The fiber laser can output dual wavelengths simultaneously or operate at single wavelength in a switchable manner. Experiment results show that with the proper SA, the peak power drift was improved from 1–2 dB to 0.31 dB and the optical signal to noise ratio was higher than 60 dB. Under the assistance of RBS feedback, the laser linewidths are compressed by around three times and the Lorentzian 3 dB linewidths of 445 Hz and 425 Hz are obtained at 1550 nm and 1554 nm, respectively.

  9. Stimulated Brillouin scattering in highly birefringent multimode tapered chalcogenide photonic crystal fiber for distributed optical sensors (Retraction Notice)

    NASA Astrophysics Data System (ADS)

    Baili, Amira; Cherif, Rim; Zghal, Mourad

    2016-09-01

    This paper, originally published on September 15, 2016, was retracted from the SPIE Digital Library on October 5, 2016, due to a high degree of similarity between specific portions of the text of the paper to the following publications: J. Tchahame, J. Beugnot, A. Kudlinski, and T. Sylvestre, "Multimode Brillouin spectrum in a long tapered birefringent photonic crystal fiber," Opt. Lett. 40, 4281-4284 (2015). doi: 10.1364/OL.40.004281 W. W. Ke, X. J. Wang and X. Tang, "Stimulated Brillouin Scattering Model in Multi-Mode Fiber Lasers," in IEEE Journal of Selected Topics in Quantum Electronics, vol. 20, no. 5, pp. 305-314, Sept.-Oct. 2014. doi: 10.1109/JSTQE.2014.2303256.

  10. A double-taper optical fiber-based radiation wave other than evanescent wave in all-fiber immunofluorescence biosensor for quantitative detection of Escherichia coli O157:H7.

    PubMed

    Zhang, Zhonghuan; Hua, Fei; Liu, Ting; Zhao, Yong; Li, Jun; Yang, Ruifu; Yang, Changxi; Zhou, Lei

    2014-01-01

    Cylindrical or taper-and-cylinder combination optical fiber probe based on evanescent wave has been widely used for immunofluorescence biosensor to detect various analytes. In this study, in contrast to the contradiction between penetration depth and analyte diameter of optical fiber probe-based evanescent wave, we demonstrate that double-taper optical fiber used in a radiation wave-based all-fiber immunofluorescence biosensor (RWAIB) can detect micron-scale analytes using Escherichia coli O157:H7 as representative target. Finite-difference time-domain method was used to compare the properties of evanescent wave and radiation wave (RW). Ray-tracing model was formulated to optimize the taper geometry of the probe. Based on a commercial multi-mode fiber, a double-taper probe was fabricated and connected with biosensor through a "ferrule connector" optical fiber connector. The RWAIB configuration was accomplished using commercial multi-mode fibers and fiber-based devices according to the "all-fiber" method. The standard sample tests revealed that the sensitivity of the proposed technique for E. coli O157:H7 detection was 10(3) cfu · mL(-1). Quantitation could be achieved within the concentration range of 10(3) cfu · mL(-1) to 107 cfu · mL(-1). No non-specific recognition to ten kinds of food-borne pathogens was observed. The results demonstrated that based on the double-taper optical fiber RWAIB can be used for the quantitative detection of micron-scale targets, and RW sensing is an alternative for traditional evanescent wave sensing during the fabrication of fiber-optic biosensors.

  11. Real-time association rate constant measurement using combination tapered fiber-optic biosensor (CTFOB) dip-probes

    NASA Astrophysics Data System (ADS)

    Simmonds, Boris; Wang, Chun-Wei; Kapoor, Rakesh

    2010-02-01

    This document reports a novel method of measuring association rate constant (ka) for antibody-antigen interaction using evanescent wave-based combination tapered fiber-optic biosensor (CTFOB) dip-probes. The method was demonstrated by measuring association rate constant for bovine serum albumin (BSA) and anti-BSA antibody interaction. "Direct method" was used for detection; goat anti-BSA "capture" antibodies were immobilized on the probe surfaces while the antigen (BSA) was directly labeled with Alexa 488 dye. The probes were subsequently submerged in 3nM Labeled BSA in egg albumin (1 mg/ml). The fluorescence signal recorded was proportional to BSA anti-BSA conjugates and continuous signal was acquired suing a fiber optic spectrometer (Ocean Optics, Inc.). A 476 nm diode laser was use as an excitation source. Association constant was estimated from a plot of signal as a function of time. Measured association rate constant ka for the binding of BSA with anti-BSA at room temperature is (8.33 +/- 0.01) x 104 M-1s-1.

  12. Low-temperature cross-talk magnetic-field sensor based on tapered all-solid waveguide-array fiber and magnetic fluids.

    PubMed

    Miao, Yinping; Ma, Xixi; Wu, Jixuan; Song, Binbin; Zhang, Hao; Zhang, Kailiang; Liu, Bo; Yao, Jianquan

    2015-08-15

    A compact fiber-optic magnetic-field sensor based on tapered all-solid waveguide-array fiber (WAF) and magnetic fluid (MF) has been proposed and experimentally demonstrated. The tapered all-solid WAF is fabricated by using a fusion splicer, and the sensor is formed by immersing the tapered all-solid WAF into the MF. The transmission spectra have been measured and analyzed under different magnetic-field intensities. Experimental results show that the acquired magnetic-field sensitivity is 44.57 pm/Oe for a linear magnetic-field intensity range from 50 to 200 Oe. All-solid WAF has very similar thermal expansion coefficient for high- and low-refractive-index glasses, so mode profile is not affected by thermal drifts. Also, magnetically induced refractive-index changes into the ferrofluid are of the order of ∼5×10(-2), while the corresponding thermally induced refractive-index changes into the ferrofluid are expected to be lower. The temperature response has also been detected, and the temperature-induced wavelength shift perturbation is less than 0.3 nm from temperature of 26.9°C-44°C. The proposed magnetic-field sensor has such advantages as low temperature sensitivity, simple structure, and ease of fabrication. It also indicates that the magnetic-field sensor based on tapered all-solid WAF and MF is helpful to reduce temperature cross-sensitivity for the measurement of magnetic field.

  13. Ultra-small Fabry-Perot cavities in tapered optical fibers

    NASA Astrophysics Data System (ADS)

    Warren-Smith, Stephen C.; André, Ricardo M.; Dellith, Jan; Bartelt, Hartmut

    2016-11-01

    The small dimensions of optical fiber sensors are of interest to biological applications, given the ability to penetrate relatively inaccessible regions. However, conventional optical fibers are larger than biological material such as cells, and thus there is a need for further miniaturization. Here we present the fabrication of ultra-small Fabry-Perot cavities written into optical micro-fibers using focused ion beam (FIB) milling. We have fabricated cavities as small as 2.8 μm and demonstrated their use for measuring refractive index. In order to achieve sensitive measurements we interrogate at visible wavelengths, thereby reducing the free spectral range of the interferometer (relative to infra-red interrogation), increasing the number of interference fringes, and allowing for the implementation of the Fourier shift method.

  14. Ultrathin niobium nanofilms on fiber optical tapers – a new route towards low-loss hybrid plasmonic modes

    PubMed Central

    Wieduwilt, Torsten; Tuniz, Alessandro; Linzen, Sven; Goerke, Sebastian; Dellith, Jan; Hübner, Uwe; Schmidt, Markus A.

    2015-01-01

    Due to the ongoing improvement in nanostructuring technology, ultrathin metallic nanofilms have recently gained substantial attention in plasmonics, e.g. as building blocks of metasurfaces. Typically, noble metals such as silver or gold are the materials of choice, due to their excellent optical properties, however they also possess some intrinsic disadvantages. Here, we introduce niobium nanofilms (~10 nm thickness) as an alternate plasmonic platform. We demonstrate functionality by depositing a niobium nanofilm on a plasmonic fiber taper, and observe a dielectric-loaded niobium surface-plasmon excitation for the first time, with a modal attenuation of only 3–4 dB/mm in aqueous environment and a refractive index sensitivity up to 15 μm/RIU if the analyte index exceeds 1.42. We show that the niobium nanofilm possesses bulk optical properties, is continuous, homogenous, and inert against any environmental influence, thus possessing several superior properties compared to noble metal nanofilms. These results demonstrate that ultrathin niobium nanofilms can serve as a new platform for biomedical diagnostics, superconducting photonics, ultrathin metasurfaces or new types of optoelectronic devices. PMID:26593209

  15. Development of combination tapered fiber-optic biosensor dip probe for quantitative estimation of interleukin-6 in serum samples

    NASA Astrophysics Data System (ADS)

    Wang, Chun Wei; Manne, Upender; Reddy, Vishnu B.; Oelschlager, Denise K.; Katkoori, Venkat R.; Grizzle, William E.; Kapoor, Rakesh

    2010-11-01

    A combination tapered fiber-optic biosensor (CTFOB) dip probe for rapid and cost-effective quantification of proteins in serum samples has been developed. This device relies on diode laser excitation and a charged-coupled device spectrometer and functions on a technique of sandwich immunoassay. As a proof of principle, this technique was applied in a quantitative estimation of interleukin IL-6. The probes detected IL-6 at picomolar levels in serum samples obtained from a patient with lupus, an autoimmune disease, and a patient with lymphoma. The estimated concentration of IL-6 in the lupus sample was 5.9 +/- 0.6 pM, and in the lymphoma sample, it was below the detection limit. These concentrations were verified by a procedure involving bead-based xMAP technology. A similar trend in the concentrations was observed. The specificity of the CTFOB dip probes was assessed by analysis with receiver operating characteristics. This analysis suggests that the dip probes can detect 5-pM or higher concentration of IL-6 in these samples with specificities of 100%. The results provide information for guiding further studies in the utilization of these probes to quantify other analytes in body fluids with high specificity and sensitivity.

  16. Intensity-modulated abrupt tapered Fiber Mach-Zehnder Interferometer for the simultaneous sensing of temperature and curvature

    NASA Astrophysics Data System (ADS)

    Raji, Y. M.; Lin, H. S.; Ibrahim, S. A.; Mokhtar, M. R.; Yusoff, Z.

    2016-12-01

    An abrupt tapered fiber In-Line Mach-Zehnder Interferometer sensor for simultaneous measurement of temperature and curvature is proposed and experimentally demonstrated. The sensor head is fabricated by arcing Corning SMF-28 using a commercial arc fusion splicer. The individual parameters discrimination was achieved by manipulating the unequal sensitivities of optical power to temperature and curvature obtained at two wavelengths within the sensing spectrum. The curvature and temperature sensitivities at λ1 (1537 nm) and λ2 (1568.7 nm) were found to be 11.8264 dBm/m-1, 12.4885 dBm/m-1 and 0.0829 dBm/°C, 0.0833 dBm/°C, respectively. The experimental results show unperturbed readings with rms deviation of ±0.1801 m-1 and ±0.0826 °C, for curvature and temperature measurements, respectively, through measurement of optical power response of the sensor. With this simultaneous sensing technique, the proposed sensor can be deployed for many field applications such as nondestructive structural health monitoring of civil infrastructure.

  17. Large-aperture CCD x-ray detector for protein crystallography using a fiber-optic taper

    NASA Astrophysics Data System (ADS)

    Strauss, Michael G.; Westbrook, Edwin M.; Naday, Istvan; Coleman, T. A.; Westbrook, Mary L.; Travis, D. J.; Sweet, Robert M.; Pflugrath, J. W.; Stanton, Martin J.

    1991-07-01

    A detector with a 114 mm aperture, based on a charge-coupled device (CCD), has been designed for x-ray diffraction studies in protein crystallography. The detector was tested on a beamline of the National Synchrotron Light Source at Brookhaven National Laboratory with a beam intensity greater than 10(superscript 9) x-ray photons/s. A fiber-optic taper, an image intensifier, and a lens demagnify, intensify, and focus the image onto a CCD having 512 X 512 pixels. A detective quantum efficiency (DQE) of 0.36 was obtained by evaluating the statistical uncertainty in the detector output. The dynamic range of a 4 X 4 pixel resolution element, comparable in size to a diffraction peak, was 10 (superscript 4). The point-spread function shows FWHM resolution of approximately 1 pixel, where a pixel on the detector face is 160 micrometers . A complete data set, consisting of forty-five 1 degree(s) rotation frames, was obtained in just 36 s of x-ray exposure to a crystal of chicken egg-white lysozyme. In a separate experiment, a lysozyme data set consisting of 495 0.1 degree(s) frames, was processed by the MADNES data reduction program, yielding symmetry R-factors for the data of 3.2- 3.5%. Diffraction images from crystals of the myosin S1 head (a equals 275 angstroms) were also recorded. The Bragg spots, only 5 pixels apart, were resolved but were not sufficiently separated to process these data. Changes in the detector design which will improve the DQE and spatial resolution are outlined. The overall performance showed that this type of detector is well suited for x-ray scattering investigations with synchrotron sources.

  18. {open_quotes}Optical guiding{close_quotes} limits on extraction efficiencies of single-pass, tapered wiggler amplifiers

    SciTech Connect

    Fawley, W.M.

    1995-12-31

    Single-pass, tapered wiggler amplifiers have an attractive feature of being able, in theory at least, of extracting a large portion of the electron beam energy into light. In circumstances where an optical FEL`s wiggler length is significantly longer than the Rayleigh length Z{sub R} corresponding to the electron beam radius, diffraction losses must be controlled via the phenomenon of {open_quotes}optical guiding{close_quotes}. Since the strength of the guiding depends upon the effective refractive index {eta}{sub r} exceeding one, and since ({eta}{sub r}-1) is inversely proportional to the optical electric field, there is a natural {open_quotes}limiting{close_quotes} mechanism to the on-axis field strength and thus the rate at which energy may be extracted from the electron beam. In particular, the extraction efficiency for a prebunched beam asymptotically grows linearly with z rather than quadratically. We present analytical and numerical simulation results concerning this behavior and discuss its applicability to various FEL designs including oscillator/amplifier-radiator configurations.

  19. Heat Extraction of Corn Fiber Hemicellulose

    NASA Astrophysics Data System (ADS)

    Benkő, Zsuzsa; Andersson, Alexandra; Szengyel, Zsolt; Gáspár, Melinda; Réczey, Kati; Stålbrand, Henrik

    Water-soluble hemicellulose was extracted from corn fiber with microwave-assisted heat treatment. The effects of treatment temperature and initial pH of the aqueous extraction media were investigated regarding hemicellulose recovery and molecular mass of the isolated polysaccharides. In treatments carried out at neutral pH (simple water extraction), it has been demonstrated that hemicellulose recovery could be increased by applying higher treatment temperatures. However, the molecular weight of isolated hemicellulose gets significantly lower. For example, 10% of the raw materials' xylan was extracted at 160°C and about 30% recovery was reached at 210°C. However, the molecular mass of the isolated polysaccharide at 210°C (5.82×104) was about half of that measured at 160°C (1.37×105). Reducing the pH with sulfuric acid resulted in shorter polymer chains (1.7×104) and lower hemicellulose yields (2.2%). Application of sodium hydroxide in the treatment showed that, compared with acid, considerably higher yields (11%) with longer polysaccharide chains (1.3×105) could be obtained.

  20. Analysis of mechanical preparations in extracted teeth using ProTaper rotary instruments: value of the safety quotient.

    PubMed

    Blum, J Y; Machtou, P; Ruddle, C; Micallef, J P

    2003-09-01

    The purpose of this study was to apply the Endographe to analyze the vertical forces and torque developed during mechanical preparations in extracted teeth. The data collected in this study may be used to calculate the safety quotient (SQ) as proposed by J.T. McSpadden. The SQ formula is defined as the torque required to break a file at D3 divided by the mean working torque required to cut dentin. The Endographe is a unique force-analyzer device equipped to measure, record, and generate graphs of the vertical forces and torque exerted during root canal preparation. All preparations were performed by endodontists in roots with narrow, more restrictive canals, larger, more open canals, or in roots sectioned in two halves. All canals, including the sectioned canals, were prepared with ProTaper files in accordance with the manufacturer's guidelines for use. For narrow canals, the mean values of the generated vertical forces (g) and torque (g.cm) varied from 80 (+/- 20) g (SX) to 232 (+/- 60) g (F2) and from 80 (+/- 24) g x cm (F1) to 150 (+/- 45) g x cm (S2), respectively. For large canals, the mean values of the generated vertical forces (g) and torque (g x cm) varied from 80 (+/- 20) g (SX) to 340 (+/- 20) g (F1) and from 31 (+/- 9) g x cm (S2) to 96 (+/- 35) g x cm (SX), respectively. The SQ varied from 0.93 to 7.95 for narrow canals and from 1.58 to 14.50 for large canals. The SQ is intended to provide values that can be analyzed to predict whether a rotary file will have a tendency to break or will work safely during clinical use. However, if the formula is going to provide useful information, it must index the "rotation to failure torque" with the "mean working torque" at a specific location along the cutting blades of a file. Additionally, this mathematical formula does not account for factors such as the concentration of forces, the way the instruments are used, or the wear of the instruments. A precise protocol for canal preparation should emphasize using

  1. Synthesis of isotropic carbon fibers from coal extracts

    SciTech Connect

    Kimber, G.M.; Vego, A.; Rantell, T.D.; Fowler, C.; Johnson, A.; Derbyshire, F.J.

    1996-12-31

    General Purpose Carbon Fibers (GPCF) are produced commercially from isotropic petroleum and coal-tar pitch precursors. Their lower cost makes them more attractive than high performance PAN (polyacrylonitrile) based or mesophase pitch-based fibers for applications where ultra-high strength or stiffness is not required. In recent years there has also been a growing interest in the use of activated carbon fibers in environmental and gas separation applications. Potentially low cost fiber precursors could be produced from coals by solvent extraction. Such extracts can be obtained in much higher yields than coal tar pitch (e.g., >50 wt.% versus <5 wt.% of coal). There is also the opportunity to widely vary the coal extract properties by control of reaction conditions (e.g., coal rank, type of solvent, reactant gas, heat treatment temperature and time) and thus alter the conditions required for fiber synthesis and the properties of the carbonized and activated fiber products.

  2. Tapered triumph

    NASA Astrophysics Data System (ADS)

    2009-01-01

    German company M2K Laser was the first in the world to successfully commercialize tapered diode lasers, and is currently the only one making gallium antimonide devices. The company's managing director speaks to Nadya Anscombe about its strategy and future.

  3. Magnetic field sensing based on magnetic-fluid-clad fiber-optic structure with taper-like and lateral-offset fusion splicing.

    PubMed

    Dong, Shaohua; Pu, Shengli; Wang, Haotian

    2014-08-11

    A kind of magnetic field sensor composed of magnetic fluid surrounding a segment of singlemode fiber is proposed. The taper-like and lateral-offset fusion splicing techniques are employed. The sensing principle is based on cladding mode interference. The interference valley wavelength or transmission loss of the sensing structure is sensitive to the external magnetic field, which is utilized for magnetic field sensing. The linear response regions are obtained in the range of 38-225 Oe and 250-475 Oe. For the valley-wavelength-shift-type sensing, the sensitivities are 14.1 pm/Oe and 26 pm/Oe at low and high field ranges, respectively. For the transmission-loss-variation-type sensing, the sensitivity of -0.024 dB/Oe is achieved for the magnetic field strength ranging from 250 to 475 Oe.

  4. Comparative Proteomic Analysis of Cotton Fiber Development and Protein Extraction Method Comparison in Late Stage Fibers

    PubMed Central

    Mujahid, Hana; Pendarvis, Ken; Reddy, Joseph S.; Nallamilli, Babi Ramesh Reddy; Reddy, K. R.; Nanduri, Bindu; Peng, Zhaohua

    2016-01-01

    The distinct stages of cotton fiber development and maturation serve as a single-celled model for studying the molecular mechanisms of plant cell elongation, cell wall development and cellulose biosynthesis. However, this model system of plant cell development is compromised for proteomic studies due to a lack of an efficient protein extraction method during the later stages of fiber development, because of a recalcitrant cell wall and the presence of abundant phenolic compounds. Here, we compared the quality and quantities of proteins extracted from 25 dpa (days post anthesis) fiber with multiple protein extraction methods and present a comprehensive quantitative proteomic study of fiber development from 10 dpa to 25 dpa. Comparative analysis using a label-free quantification method revealed 287 differentially-expressed proteins in the 10 dpa to 25 dpa fiber developmental period. Proteins involved in cell wall metabolism and regulation, cytoskeleton development and carbohydrate metabolism among other functional categories in four fiber developmental stages were identified. Our studies provide protocols for protein extraction from maturing fiber tissues for mass spectrometry analysis and expand knowledge of the proteomic profile of cotton fiber development. PMID:28248216

  5. Biconical tapered optical fiber biosensor for measuring refractive index of a-amino acids in aqueous D-glucose and sucrose solution

    NASA Astrophysics Data System (ADS)

    Zibaii, M. I.; Latifi, H.; Karami, M.; Gholami, M.; Hosseini, S. M.; Ghezelayagh, M. H.

    2010-04-01

    A single-mode biconical tapered optical fiber (BTOF) sensor was utilized for sensing the variation of refractive index (RI) with concentration of D-glucose in double distilled deionized water and measuring of RI of amino acids (AAs) in carbohydrate solutions. This method showed a rewarding ability in understanding the basis of biomolecular interactions in biological systems. The BTOF is fabricated by heat pulling method, utilizing a CO2 laser. The detection limit of the BTOF was 50 ppb for the D-glucose concentration ranging from 0 to 80 ppm, and RI detection limit corresponding to these concentrations in the range at 1.3333 to 1.3404 was 5.4×10-6 as a refractometer sensor. The response of the BTOF shows that the different kinds of interactions of various groups of AAs such as L-alanine, L-leucine, and L-cystein with D-glucose, sucrose and water molecules depend on functional groups in AAs such as OH, SH;CH2;NH3+ ,COO-. These results can be interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.

  6. Excitation beyond the monochromatic laser limit: simultaneous 3-D confocal and multiphoton microscopy with a tapered fiber as white-light laser source.

    PubMed

    Betz, Timo; Teipel, Jörn; Koch, Daniel; Härtig, Wolfgang; Guck, Jochen; Käs, Josef; Giessen, Harald

    2005-01-01

    Confocal and multiphoton microscopy are essential tools in modern life sciences. They allow fast and highly resolved imaging of a steadily growing number of fluorescent markers, ranging from fluorescent proteins to quantum dots and other fluorophores, used for the localization of molecules and the quantitative detection of molecular properties within living cells and organisms. Up to now, only one physical limitation seemed to be unavoidable. Both confocal and multiphoton microscopy rely on lasers as excitation sources, and their monochromatic radiation allows only a limited number of simultaneously usable dyes, which depends on the specific number of laser lines available in the used microscope. We have overcome this limitation by successfully replacing all excitation lasers in a standard confocal microscope with pulsed white light ranging from 430 to 1300 nm generated in a tapered silica fiber. With this easily reproducible method, simultaneous confocal and multiphoton microscopy was demonstrated. By developing a coherent and intense laser source with spectral width comparable to a mercury lamp, we provide the flexibility to excite any desired fluorophore combination.

  7. Vertical force and torque analysis during mechanical preparation of extracted teeth using hand ProTaper instruments.

    PubMed

    Glavičić, Snježana; Anić, Ivica; Braut, Alen; Miletić, Ivana; Borčić, Josipa

    2011-08-01

    The purpose was to measure and analyse the vertical force and torque developed in the wider and narrower root canals during hand ProTaper instrumentation. Twenty human incisors were divided in two groups. Upper incisors were experimental model for the wide, while the lower incisors for the narrow root canals. Measurements of the force and torque were done by a device constructed for this purpose. Differences between the groups were statistically analysed by Mann-Whitney U-test with the significance level set to P<0.05. Vertical force in the upper incisors ranged 0.25-2.58 N, while in the lower incisors 0.38-6.94 N. Measured torque in the upper incisors ranged 0.53-12.03 Nmm, while in the lower incisor ranged 0.94-10.0 Nmm. Vertical force and torque were higher in the root canals of smaller diameter. The increase in the contact surface results in increase of the vertical force and torque as well in both narrower and wider root canals.

  8. Tapered optical fibres for sensing

    NASA Astrophysics Data System (ADS)

    Martan, Tomas; Kanka, Jiri; Kasik, Ivan; Matejec, Vlastimil

    2008-11-01

    Recently, optical fibre tapers have intensively been investigated for many applications e.g. in telecommunications, medicine and (bio-) chemical sensing. The paper deals with enhancement of evanescent-field sensitivity of the solid-core microstructured fibre with steering-wheel air-cladding. Enhancement of a performance of the microstructured fibre is based on reduction of fibre core diameter down to narrow filament by tapering thereby defined part of light power is guided by an evanescent wave traveling in axial cladding air holes. The original fibre structure with outer diameter of 125 µm was reduced 2×, 2.5×, 3.33×, and 4× for increasing relatively small intensity overlap of guided core mode at wavelength of 1.55 μm with axial air holes. The inner structures of tapered microstructured fibre with steering-wheel aircladding were numerically analyzed and mode intensity distributions were calculated using the FDTD technique. Analyzed fiber tapers were prepared by constructed fibre puller employing 'flame brush technique'.

  9. Octave spanning supercontinuum in an As₂S₃ taper using ultralow pump pulse energy.

    PubMed

    Hudson, Darren D; Dekker, Stephen A; Mägi, Eric C; Judge, Alexander C; Jackson, Stuart D; Li, Enbang; Sanghera, J S; Shaw, L B; Aggarwal, I D; Eggleton, Benjamin J

    2011-04-01

    An octave spanning spectrum is generated in an As₂S₃ taper via 77 pJ pulses from an ultrafast fiber laser. Using a previously developed tapering method, we construct a 1.3 μm taper that has a zero-dispersion wavelength around 1.4 μm. The low two-photon absorption of sulfide-based chalcogenide fiber allows for higher input powers than previous efforts in selenium-based chalcogenide tapered fibers. This higher power handling capability combined with input pulse chirp compensation allows an octave spanning spectrum to be generated directly from the taper using the unamplified laser output.

  10. Pain fiber anesthetic reduces brainstem Fos after tooth extraction.

    PubMed

    Badral, B; Davies, A J; Kim, Y H; Ahn, J S; Hong, S D; Chung, G; Kim, J S; Oh, S B

    2013-11-01

    We recently demonstrated that pain-sensing neurons in the trigeminal system can be selectively anesthetized by co-application of QX-314 with the TRPV1 receptor agonist, capsaicin (QX cocktail). Here we examined whether this new anesthetic strategy can block the neuronal changes in the brainstem following molar tooth extraction in the rat. Adult male Sprague-Dawley rats received infiltration injection of anesthetic 10 min prior to lower molar tooth extraction. Neuronal activation was determined by immunohistochemistry for the proto-oncogene protein c-Fos in transverse sections of the trigeminal subnucleus caudalis (Sp5C). After tooth extraction, c-Fos-like immunoreactivity (Fos-LI) detected in the dorsomedial region of bilateral Sp5C was highest at 2 hrs (p < .01 vs. naïve ipsilateral) and declined to pre-injury levels by 8 hrs. Pre-administration of the QX cocktail significantly reduced to sham levels Fos-LI examined 2 hrs after tooth extraction; reduced Fos-LI was also observed with the conventional local anesthetic lidocaine. Pulpal anesthesia by infiltration injection was confirmed by inhibition of the jaw-opening reflex in response to electrical tooth pulp stimulation. Our results suggest that the QX cocktail anesthetic is effective in reducing neuronal activation following tooth extraction. Thus, a selective pain fiber 'nociceptive anesthetic' strategy may provide an effective local anesthetic option for dental patients in the clinic.

  11. Radiation Effects on Fused Biconical Taper Wavelength Division Multiplexers

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roman C.; Swift, Gary M.; Dubovitsky, Serge; Bartman, Randall K.; Barnes, Charles E.; Dorsky, Leonard

    1994-01-01

    The effects of radiation on fused biconical taper wavelength division multiplexers are presented. A theoretical model indicates that index changes in the fiber are primarily responsible for the degradation of these devices.

  12. Compression Molding of CFRTP Used with Carbon Fiber Extracted from CFRP Waste

    NASA Astrophysics Data System (ADS)

    Kimura, Teruo; Ino, Haruhiro; Nishida, Yuichi; Aoyama, Naoki; Shibata, Katsuji

    This study investigated a compression molding method of carbon fiber reinforced thermoplastics (CFRTP) made of carbon fiber extracted from CFRP waste. The short carbon fibers were mixed with polyester fibers using a papermaking method to make the preform sheet of compression molding. The waste obtained from a textile water jet loom was used as a matrix material. The setting speed of each fiber during the papermaking process was regulated by using a dispersing agent to obtain the good dispersion of each fiber. Laminated preform sheets combined with polyester fibers and carbon fibers were compressed with heating at 300°C and then the polyester fiber was melted as a matrix material. It was cleared from the experimental results that the mechanical properties of molded CFRTP largely depends on both the fiber dispersion and the content of carbon fiber in the preform.

  13. Pressure variation assisted fiber extraction and development of high performance natural fiber composites and nanocomposites

    NASA Astrophysics Data System (ADS)

    Markevicius, Gediminas

    It is believed, that due to the large surface areas provided by the nano scale materials, various composite properties could be enhanced when such particles are incorporated into a polymer matrix. There is also a trend of utilizing natural resources or reusing and recycling materials that are already available for the fabrication of the new composite materials. Cellulose is the most abundant natural polymer on the planet, and therefore it is not surprising to be of interest for composite fabrication. Basic structures of cellulose, comprised of long polysaccharide chains, are the building blocks of cellulose nano fibers. Nano fibers are further bound into micro fibrils and macro fibers. Theoretically pure cellulose nano fibers have tremendous strengths, and therefore are some of the most sought after nano particles. The fiber extraction however is a complex task. The ultrasound, which creates pressure variation in the medium, was employed to extract nano-size cellulose particles from microcrystalline cellulose (MCC). The length and the intensity of the cavitations were evaluated. Electron microscopy studies revealed that cellulose nanoparticles were successfully obtained from the MCC after ultrasound treatment of just 30 minutes. Structure of the fractionated cellulose was also analyzed with the help of X-ray diffraction, and its thermal properties were evaluated with the help of differential scanning calorimetry (DSC). Ultrasound treatment performed on the wheat straw, kenaf, and miscanthus particles altered fiber structure as a result of the cavitation. The micro fibers were generated from these materials after they were subjected to NaOH treatment followed by the ultrasound processing. The potential of larger than nano-sized natural fibers to be used for composite fabrication was also explored. The agricultural byproducts, such as wheat or rice straw, as well as other fast growing crops as miscanthus or kenaf, are comprised of three basic polymers. Just like in

  14. Tapered structure construction

    SciTech Connect

    Smith, Eric D.; Takata, Rosalind K.; Slocum, Alexander H.; Nayfeh, Samir A.

    2016-04-05

    Feeding stock used to form a tapered structure into a curving device such that each point on the stock undergoes rotational motion about a peak location of the tapered structure; and the stock meets a predecessor portion of stock along one or more adjacent edges.

  15. Lightwave coupler utilizing a tapered buffer layer.

    PubMed

    Kishioka, K

    1988-06-01

    We discuss the performance of a lightwave coupler utilizing a tapered buffer layer. The coupler with a ridge waveguide is fabricated on a glass substrate and high coupling efficiencies of 75% and 50% are measured for the operations of coupling from the waveguide to a light beam and from the laser beam into the waveguide, respectively. Further, experimental results of the rigid connection between the optical fiber and the waveguide are demonstrated. We also describe how the coupler differs from the conventional tapered guiding-layer coupler.

  16. Emulsion-liquid-membrane extraction of copper using a hollow-fiber contactor

    SciTech Connect

    Hu, S.Y.B.; Wiencek, J.M.

    1998-03-01

    A novel extraction technique using an emulsion liquid membrane within a hollow-fiber contactor was developed and utilized to extract copper using LIX 84 extractant. Emulsion liquid membranes are capable of extracting metals from dilute waste streams to levels much below those possible by equilibrium-limited solvent extraction. Utilizing an emulsion liquid membrane within a hollow-fiber contactor retains the advantages of emulsion-liquid-membrane extraction, namely, simultaneous extraction and stripping, while eliminating problems encountered in dispersive contacting methods, such as swelling and leakage of the liquid membrane. Mathematical models for extraction in hollow-fiber contactors were developed. The models satisfactorily predict the outcome of both simple solvent extraction and emulsion-liquid-membrane extraction of copper by LIX 84 in a hollow-fiber contactor over a wide range of conditions. Emulsion-liquid-membrane extraction performs exceptionally well when the extraction is close to equilibrium limit. It is also capable of extracting a solute f/rom very dilute solutions. Stability of the liquid membrane is not crucial when used in hollow-fiber contactors; the surfactant in liquid membrane can be reduced or even eliminated without severely impairing the performance.

  17. ZnO nanorod array polydimethylsiloxane composite solid phase micro-extraction fiber coating: fabrication and extraction capability.

    PubMed

    Wang, Dan; Wang, Qingtang; Zhang, Zhuomin; Chen, Guonan

    2012-01-21

    ZnO nanorod array coating is a novel kind of solid-phase microextraction (SPME) fiber coating which shows good extraction capability due to the nanostructure. To prepare the composite coating is a good way to improve the extraction capability. In this paper, the ZnO nanorod array polydimethylsiloxane (PDMS) composite SPME fiber coating has been prepared and its extraction capability for volatile organic compounds (VOCs) has been studied by headspace sampling the typical volatile mixed standard solution of benzene, toluene, ethylbenzene and xylene (BTEX). Improved detection limit and good linear ranges have been achieved for this composite SPME fiber coating. Also, it is found that the composite SPME fiber coating shows good extraction selectivity to the VOCs with alkane radicals.

  18. Mach-Zehnder interferometer based on tapered PCF with an up-tapered joint for curvature, strain and temperature interrogation

    NASA Astrophysics Data System (ADS)

    Narayan Dash, Jitendra; Jha, Rajan

    2016-10-01

    We propose a Mach-Zehnder interferometric sensor based on tapered Photonic Crystal Fiber (PCF) with up-tapered collapsed region for measurement of parameters such as curvature, strain and temperature. The up-tapered collapsed region helps in excitation of the cladding modes in PCF and these modes interfere with each other at the tapered region of PCF which is completely collapsed. Three tapered PCFs with varying geometry are fabricated and their effect on curvature sensitivity is analyzed. Experimental results show that the proposed sensor has a curvature sensitivity of 7.56 nm m-1 with negligible hysteresis effect. Moreover, the proposed sensor shows a strain sensitivity of 1.6 pm/μɛ along with a maximum temperature sensitivity of 51.6 pm °C-1. In addition to this, the response of the interference pattern to all these parameters is found to be linear.

  19. Interactive Exploration and Visualization using MetaTracts extracted from Carbon Fiber Reinforced Composites.

    PubMed

    Bhattacharya, Arindam; Weissenbock, Johannes; Wenger, Rephael; Amirkhanov, Artem; Kastner, Johann; Heinzl, Christoph

    2016-06-16

    This work introduces a tool for interactive exploration and visualization using MetaTracts. MetaTracts is a novel method for extraction and visualization of individual fiber bundles and weaving patterns from X-ray computed tomography (XCT) scans of endless carbon fiber reinforced polymers (CFRPs). It is designed specifically to handle XCT scans of low resolutions where the individual fibers are barely visible, which makes extraction of fiber bundles a challenging problem. The proposed workflow is used to analyze unit cells of CFRP materials integrating a recurring weaving pattern. First, a coarse version of integral curves is used to trace subsections of the individual fiber bundles in the woven CFRP materials. We call these sections MetaTracts. In the second step, these extracted fiber bundle sections are clustered using a two-step approach: first by orientation, then by proximity. The tool can generate volumetric representations as well as surface models of the extracted fiber bundles to be exported for further analysis. In addition a custom interactive tool for exploration and visual analysis of MetaTracts is designed. We evaluate the proposed workflow on a number of real world datasets and demonstrate that MetaTracts effectively and robustly identifies and extracts fiber bundles.

  20. Cellulose fibers extracted from rice and oat husks and their application in hydrogel.

    PubMed

    Oliveira, Jean Paulo de; Bruni, Graziella Pinheiro; Lima, Karina Oliveira; Halal, Shanise Lisie Mello El; Rosa, Gabriela Silveira da; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2017-04-15

    The commercial cellulose fibers and cellulose fibers extracted from rice and oat husks were analyzed by chemical composition, morphology, functional groups, crystallinity and thermal properties. The cellulose fibers from rice and oat husks were used to produce hydrogels with poly (vinyl alcohol). The fibers presented different structural, crystallinity, and thermal properties, depending on the cellulose source. The hydrogel from rice cellulose fibers had a network structure with a similar agglomeration sponge, with more homogeneous pores compared to the hydrogel from oat cellulose fibers. The hydrogels prepared from the cellulose extracted from rice and oat husks showed water absorption capacity of 141.6-392.1% and high opacity. The highest water absorption capacity and maximum stress the compression were presented by rice cellulose hydrogel at 25°C. These results show that the use of agro-industrial residues is promising for the biomaterial field, especially in the preparation of hydrogels.

  1. Tapered, tubular polyester fabric

    NASA Technical Reports Server (NTRS)

    Lapointe, Donat J. E. (Inventor); Wright, Lawrence T. (Inventor); Vincent, Laurence J. (Inventor)

    1987-01-01

    A tapered tubular polyester sleeve is described to serve as the flexible foundation for a spacesuit limb covering. The tube has a large end and a small end with a length to be determined. The ratio of taper is also determined by scale factors. All the warp yarns extend to the large end. A requisite number of warp yarns extend the full length of the sleeve. Other warp yarns extend from the large end but are terminated along the length of the sleeve. It is then woven with a filling yarn which extends in a full circle along the full length of the sleeve to thereby define the tapered sleeve. The sleeve after fabrication is then placed on a mandrel, heated in an oven, and then attached to the arm or other limb of the spacesuit.

  2. Tapered, tubular polyester fabric

    NASA Technical Reports Server (NTRS)

    LaPointe, Donat J. E. (Inventor); Vincent, Laurence J. (Inventor); Wright, Lawrence T. (Inventor)

    1988-01-01

    A tapered tubular polyester sleeve as set forth. It has a large end 12 and a small end 14 with a length to be determined. The ratio of taper is also determined by scale factors. All the warp yarns extend to the large end 12. A requisite number of warp yarns 16 extend the full length of the sleeve. Other warp yarns exemplified at 18, 22, 26, 28, 30 and 32 extend from the large end but are terminated along the length of the sleeve. It is then woven with a filling yarn 40 which extends in a full circle along the full length of the sleeve to thereby define the tapered sleeve. The sleeve after fabrication is then placed on a mandrel 42, heated in an oven 44 and is thereafter placed on the arm or other limb of a space suit exemplified at 50.

  3. Plasma cholesterol-lowering effect on rats of dietary fiber extracted from immature plants.

    PubMed

    Nishimura, N; Taniguchi, Y; Kiriyama, S

    2000-12-01

    Crude dietary fiber samples were prepared from beet, cabbage, Japanese radish, onion and mung bean sprouts (BF, CF, RF, OF and MF, respectively). These samples contained total dietary fiber at the levels of 814, 699, 760, 693 and 666 g/kg, respectively. To examine the effect of these dietary fiber sources on the plasma cholesterol concentration, male Sprague-Dawley rats were fed on a fiber-free (FF) diet or on an FF diet supplemented with 5% or 10% dietary fiber. Dietary fiber extracted from vegetables, wood cellulose (CL), pectin (PE) and guar gum (GG) were used as the fiber sources. Compared with the rats fed on the FF diet, a significant reduction in the plasma cholesterol concentration was observed in the rats fed on BF, CF, RF, MF, PE or GG after a 21-d feeding period. Cecal acetate, n-butyrate and total short-chain fatty acids were significantly higher in the rats fed on these dietary fibers, except for CF, than in those fed on the FF diet. A negative correlation was apparent between the total dietary fiber content, hemicellulose content and pectin content of each dietary fiber source and the plasma cholesterol concentration. These results suggest that some vegetable fibers exert a plasma cholesterol-lowering effect through cecal fermentation of these fibers.

  4. Collection and separation of extract in dispersive liquid-liquid microextraction with hollow fiber.

    PubMed

    Wang, Kun; Li, Na; Lei, Lei; Yang, Xiao; Wang, Zhibing; Li, Dan; Zang, Shuang; Zhang, Hanqi; Yu, Aimin; Zhang, Ziwei

    2016-05-01

    Dispersive liquid-liquid microextraction combined with collection of the extraction phase with the hollow fiber was applied to the extraction of estrogens from environmental water samples. 1-Undecanol with relatively lower toxicity was used as the extraction solvent. The hollow fiber was used to collect the extraction phase containing the analytes from the aqueous phase. Hollow fibers collecting the extraction phase were eluted with acetonitrile and the resulting eluate was analyzed by high performance liquid chromatography. Several parameters, including pH of sample, the type and volume of the extraction and dispersive solvent, salt concentration, extraction time, and collection time were optimized. Under the optimal experimental conditions, the limits of detection for estriol, 17α-estradiol, and ethynylestradiol were 4.58, 1.41, and 1.41 μg L(-1), respectively. When the present method was applied to the analysis of real water samples, the recoveries of estrogens at two spiked levels were in the range of 55.8-107.4%. In this method, the separation of the extraction phase and aqueous phase becomes easy with no need for centrifugation, refrigeration-thaw, or any special device. The hollow fiber was commercially available and the collection procedure was easy to perform, which make the present method have potential for automation and wide promotion. Small sizes of pores on the walls of the hollow fibers can block large molecules, which makes the present method have the potential for the treatment of complex matrices.

  5. Compound taper milling machine

    NASA Technical Reports Server (NTRS)

    Campbell, N. R.

    1969-01-01

    Simple, inexpensive milling machine tapers panels from a common apex to a uniform height at panel edge regardless of the panel perimeter configuration. The machine consists of an adjustable angled beam upon which the milling tool moves back and forth above a rotatable table upon which the workpiece is held.

  6. Analysis of Dyes Extracted from Millimeter-Size Nylon Fibers by Micellar Electrokinetic Chromatography

    SciTech Connect

    Lewis, L.A.

    2001-07-30

    The Learning Objective is to present to the forensic community a potential qualitative/quantitative method for trace-fiber color comparisons using micellar electrokinetic chromatography (MEKC). Developing a means of analyzing extracted dye constituents from millimeter-size nylon fiber samples was the objective of this research initiative. Aside from ascertaining fiber type, color evaluation and source comparison of trace-fiber evidence plays a critical role in forensic-fiber examinations. Literally thousands of dyes exist to date, including both natural and synthetic compounds. Typically a three-color-dye combination is employed to affect a given color on fiber material. The result of this practice leads to a significant number of potential dye combinations capable of producing a similar color and shade. Since a typical forensic fiber sample is 2 mm or less in length, an ideal forensic dye analysis would qualitatively and quantitatively identify the extracted dye constituents from a sample size of 1 mm or smaller. The goal of this research was to develop an analytical method for comparing individual dye constituents from trace-fiber evidence with dyes extracted from a suspected source, while preserving as much of the original evidence as possible.

  7. Antimicrobial and antiviral activities of polyphenolics from Cocos nucifera Linn. (Palmae) husk fiber extract.

    PubMed

    Esquenazi, Daniele; Wigg, Marcia D; Miranda, Mônica M F S; Rodrigues, Hugo M; Tostes, João B F; Rozental, Sonia; da Silva, Antonio J R; Alviano, Celuta S

    2002-12-01

    The decoction of Cocos nucifera L. husk fiber has been used in northeastern Brazil traditional medicine for treatment of diarrhea and arthritis. Water extract obtained from coconut husk fiber and fractions from adsorption chromatography revealed antimicrobial activity against Staphylococcus aureus. The crude extract and one of the fractions rich in catechin also showed inhibitory activity against acyclovir-resistant herpes simplex virus type 1 (HSV-1-ACVr). All fractions were inactive against the fungi Candida albicans, Fonsecaea pedrosoi and Cryptococcus neoformans. Catechin and epicatechin together with condensed tannins (B-type procyanidins) were demonstrated to be the components of the water extract.

  8. Optical coupling and splitting with two parallel waveguide tapers.

    PubMed

    Tao, S H

    2011-01-17

    A coupling and splitting device comprising a width taper and a spatial-modulated subwavelength grating waveguide (SSGW) is proposed. The width taper is a waveguide with increasing width and the SSGW is a waveguide grating whose width and thickness are constant but the filling factor increases along the light propagation. Thus, the effective index of the subwavelength grating increases according to the effective medium theory. Light of orthogonal polarizations from a single-mode fiber can be coupled efficiently with the two parallel tapers. Furthermore, the coupled lights of orthogonal polarizations in the two tapers can be further split with connecting bent waveguides. Fabrication of the device is fully compatible with current complementary metal oxide semiconductor technology.

  9. Extraction and functional reformation of thick filaments in chemically skinned molluscan catch muscle fibers.

    PubMed

    Tanaka, M; Tanaka, H

    1979-02-01

    A method for the almost complete extraction of myosin from smooth muscle fibers of the anterior byssal retractor muscle (ABRM) of Mytilus edulis was developed, and functional reformation of thick filaments in the fibers was achieved. Complete removal of myosin from the glycerol-extracted ABRM fibers with a solution containing 600 mM KCl, 5 mM MgCl2, and 5 mM ATP was difficult. However, successive treatments of the ABRM fibers with glycerol and saponin made the plasma membrane permeable to Mg-ATP and myosin. The extraction of myosin completely eliminated the tension induced by the addition of Mg-ATP. Partial recovery of tension development was observed by irrigation of myosin into fibers from which myosin had been extracted. Similar results were obtained using rabbit myosin instead of ABRM myosin. Addition of heavy meromyosin, on the other hand, had a suppressive effect on the tension development, as is the case in glycerinated rabbit psoas muscle fibers.

  10. Tapered capillary optics

    DOEpatents

    Hirsch, Gregory

    1998-01-01

    A metal or glass wire is etched with great precision into a very narrowly tapering cone which has the shape of the desired final capillary-optics bore. By controlling the rate of removal of the wire from an etchant bath, a carefully controlled taper is produced. A sensor measures the diameter of the wire as it leaves the surface of the etchant. This signal is used for feedback control of the withdrawal speed. The etched wire undergoes a treatment to produce an extremely low surface-roughness. The etched and smoothed wire is coated with the material of choice for optimizing the reflectivity of the radiation being focused. This could be a vacuum evaporation, sputtering, CVD or aqueous chemical process. The coated wire is either electroplated, built up with electroless plating, or encapsulated in a polymer cylinder such as epoxy to increase the diameter of the wire for easier handling and greater robustness. During this process, the wire is vertically oriented and tensioned to assure that the wire is absolutely straight. The coated and electroformed wire is bonded to a flat, rigid substrate and is then periodically segmented by cutting or etching a series of narrow slits or grooves into the wire. The wire is vertically oriented and tensioned during the bonding process to assure that it is straight. The original wire material is then chemically etched away through the slits or otherwise withdrawn to leave the hollow internal bore of the final tapered-capillary optical element.

  11. Preparation and application of a coated-fiber needle extraction device.

    PubMed

    Lou, Dawei; Chen, Huijun; Wang, Xiyue; Lian, Lili; Zhu, Bo; Yang, Qiaoling; Guo, Tingxiu; Li, Qiuying; Wang, Runnan; Guo, Xiaoyang

    2016-10-01

    In this study, a needle-trap device with fibers coated with a molecularly imprinted polymer was developed for separation. A number of heat-resistant Zylon filaments were longitudinally packed into a glass capillary, followed by coating with a molecularly imprinted polymer. Then, the molecularly imprinted polymer coating was copolymerized and anchored onto the surface of the fibers. The bundle of synthetic fibers coated with the molecularly imprinted polymer was packed into a 21G stainless-steel needle and served as an extraction medium. The coated-fiber needle extraction device was used to extract volatile organic compounds from paints and gasoline effectively. Subsequently, the extracted volatile organic compounds were analyzed by gas chromatography. Calibration curves of gaseous benzene, toluene, ethylbenzene, and o-xylene in the concentration range of 1-250 μg/L were obtained to evaluate the method, acceptable linearity was attended with correlation coefficients above 0.998. The limit of detection of benzene, toluene, ethylbenzene, and o-xylene was 11-20 ng/L using the coated-fiber needle-trap device. The relative standard deviation of needle-to-needle repeatability was less than 8% with an extraction time of 20 min. The loss rates after storage for 3 and 7 days at room temperature were less than 30%.

  12. In-syringe dispersive solid phase extraction: a novel format for electrospun fiber based microextraction.

    PubMed

    Zhu, Gang-Tian; He, Xiao-Mei; Cai, Bao-Dong; Wang, Han; Ding, Jun; Yuan, Bi-Feng; Feng, Yu-Qi

    2014-12-07

    A novel in-syringe dispersive solid phase extraction (dSPE) system using electrospun silica fibers as adsorbents has been developed in the current work. A few milligrams of electrospun silica fibers were incubated in sample solution in the barrel of a syringe for microextraction assisted by vortex. Due to the benefit of dispersion and the high mass transfer rate of the sub-microscale electrospun silica fibers, the extraction equilibrium was achieved in a very short time (less than 1 min). Moreover, thanks to the long fibrous properties of electrospun fibers, the separation of the adsorbent from sample solution was easily achieved by pushing out the sample solution which therefore simplified the sample pretreatment procedure. Besides, the analytical throughput was largely increased by using a multi-syringe plate to perform the extraction experiment. The performance of the in-syringe dSPE device was evaluated by extraction of endogenous cytokinins from plant tissue samples based on the hydrophilic interaction. Six endogenous cytokinins in 20 mg of Oryza sativa L. (O. sativa) leaves were successfully determined under optimized conditions using in-syringe dSPE combined with liquid chromatography-mass spectrometry analysis. The results demonstrated that the in-syringe dSPE method was a rapid and high-throughput strategy for the extraction of target compounds, which has great potential in microscale sample pretreatment using electrospun fibers.

  13. Effect of Dietary Fiber Extracted from Algelica keiskei Koidz on the Quality Characteristics of Chicken Patties

    PubMed Central

    Choi, Yun-Sang; Kim, Hyun-Wook; Kim, Young-Boong; Jeon, Ki-Hong

    2015-01-01

    In this study, we evaluated the effects of dietary fiber extracted from Algelica keiskei Koidz on the chemical composition, cooking characteristics, and sensory properties of chicken patties. The chicken patties with Algelica keiskei Koidz dietary fiber had significantly higher moisture and ash content, and yellowness than the control sample (p<0.05). Energy value, cooking loss, reduction in diameter, reduction in thickness, lightness, redness, hardness, cohesiveness, gumminess, and chewiness of the control samples was significantly higher than chicken patties with Algelica keiskei Koidz dietary fiber (p<0.05). The sensory evaluation indicated that the greatest overall acceptability in chicken patties was achieved at Algelica keiskei Koidz dietary fiber levels of 1% and 2%. Chicken patties supplemented with 2% Algelica keiskei Koidz dietary fiber had improved quality characteristics. PMID:26761844

  14. Superelasticity of Cu-Ni-Al shape-memory fibers prepared by melt extraction technique

    NASA Astrophysics Data System (ADS)

    Li, Dong-yue; Zhang, Shu-ling; Liao, Wei-bing; Geng, Gui-hong; Zhang, Yong

    2016-08-01

    In the paper, a melt extraction method was used to fabricate Cu-4Ni-14Al (wt%) fiber materials with diameters between 50 and 200 μm. The fibers exhibited superelasticity and temperature-induced martensitic transformation. The microstructures and superelasticity behavior of the fibers were studied via scanning electron microscopy (SEM) and a dynamic mechanical analyzer (DMA), respectively. Appropriate heat treatment further improves the plasticity of Cu-based alloys. The serration behavior observed during the loading process is due to the multiple martensite phase transformation.

  15. Endfire tapered slot antenna characteristics

    NASA Technical Reports Server (NTRS)

    Schaubert, D. H.

    1989-01-01

    Typical configurations and operating characteristics for endfire tapered slot antennas are described. The feed transition modeling and moment method modeling techniques are utilized to predict antenna performance. The radiation pattern and cross polarization properties for the linearly tapered slot antennas are examined. Endfire tapered slot antennas are applicable for wide-band scanning arrays and focal plane arrays for imaging and multiple beam reflector systems.

  16. Modeling and multidimensional optimization of a tapered free electron laser

    NASA Astrophysics Data System (ADS)

    Jiao, Y.; Wu, J.; Cai, Y.; Chao, A. W.; Fawley, W. M.; Frisch, J.; Huang, Z.; Nuhn, H.-D.; Pellegrini, C.; Reiche, S.

    2012-05-01

    Energy extraction efficiency of a free electron laser (FEL) can be greatly increased using a tapered undulator and self-seeding. However, the extraction rate is limited by various effects that eventually lead to saturation of the peak intensity and power. To better understand these effects, we develop a model extending the Kroll-Morton-Rosenbluth, one-dimensional theory to include the physics of diffraction, optical guiding, and radially resolved particle trapping. The predictions of the model agree well with that of the GENESIS single-frequency numerical simulations. In particular, we discuss the evolution of the electron-radiation interaction along the tapered undulator and show that the decreasing of refractive guiding is the major cause of the efficiency reduction, particle detrapping, and then saturation of the radiation power. With this understanding, we develop a multidimensional optimization scheme based on GENESIS simulations to increase the energy extraction efficiency via an improved taper profile and variation in electron beam radius. We present optimization results for hard x-ray tapered FELs, and the dependence of the maximum extractable radiation power on various parameters of the initial electron beam, radiation field, and the undulator system. We also study the effect of the sideband growth in a tapered FEL. Such growth induces increased particle detrapping and thus decreased refractive guiding that together strongly limit the overall energy extraction efficiency.

  17. Compact and efficient large cross-section SOI rib waveguide taper optimized by a genetic algorithm

    NASA Astrophysics Data System (ADS)

    Liu, Yujin; Wang, Xi; Dong, Ying; Wang, Xiaohao

    2016-01-01

    A genetic algorithm is applied to optimize a taper between a large cross-section silicon-on-insulator (SOI) rib waveguide and a single-mode fiber to achieve an ultra-compact and highly efficient coupling structure. The coupling efficiency is taken as the objective function of the genetic algorithm in the taper optimization process. To apply the optimization algorithm, the taper is segmented into several sections. Three encoding forms and a two-step optimization strategy are adopted in the optimization process, resulting in a 10μm long taper with a coupling efficiency of 93.30% in quasi-TE mode at 1550nm. The characteristics of the optimized taper including the field profile, spectrum and fabrication tolerances in both horizontal and vertical directions are investigated via a three dimensional eigenmode expansion (EME) method, indicating that the optimized taper is compatible with the prevailing integrated circuit (IC) processing technology.

  18. Distributed fiber vibration measurement based on phase extraction from time-gated digital OFDR

    NASA Astrophysics Data System (ADS)

    Wang, Shuai; Fan, Xinyu; Liu, Qingwen; He, Zuyuan

    2015-09-01

    We demonstrate a novel distributed fiber vibration sensor based on the phase extraction from time-gated digital optical frequency domain reflectometry (TGD-OFDR), which have an advantage of wide dynamic range. With the much improved signal to noise ratio (SNR) compared to conventional phase-sensitive optical time domain reflectometry (OTDR), the phase of optical signals is extracted over a long distance up to 29 km with 2.2 m spatial resolution.

  19. Intensity modulated SMF cascaded tapers with a hollow core PCF based microcavity for curvature sensing

    NASA Astrophysics Data System (ADS)

    Dass, Sumit; Narayan Dash, Jitendra; Jha, Rajan

    2016-03-01

    We propose a highly sensitive curvature sensor based on cascaded single mode fiber (SMF) tapers with a microcavity. The microcavity is created by splicing a small piece of hollow core photonic crystal fiber (HCPCF) at the end of an SMF to obtain a sharp interference pattern. Experimental results show that two SMF tapers enhance the curvature sensitivity of the system and by changing the tapering parameters of the second taper, the curvature sensitivity of the system can be tailored, together with the fringe contrast of the interference pattern. A maximum curvature sensitivity of 10.4 dB/m-1 is observed in the curvature range 0 to 1 m-1 for a second taper diameter of 18 μm. The sensing setup is highly stable and shows very low temperature sensitivity. As the interrogation is intensity based, a low cost optical power meter can be utilized to determine the curvature.

  20. Electrospun poly(vinyl alcohol) fiber mats as carriers for extracts from the fruit hull of mangosteen.

    PubMed

    Opanasopit, Praneet; Ruktanonchai, Uracha; Suwantong, Orawan; Panomsuk, Suwannee; Ngawhirunpat, Tanasait; Sittisombut, Chavalit; Suksamran, Tittaya; Supaphol, Pitt

    2008-01-01

    Electrospinning is a process used to produce ultrafine fibers with diameters in the nanometer range. Electrospun fiber mats have high potentials for biomedical uses, due to their high surface area and ease of drug incorporation into the fibers. They can be used as carriers for drug delivery and can enhance drug release and skin permeability. The aim of this study was to prepare electrospun fiber mats and to incorporate extracts from the fruit hull of mangosteen. Antioxidant activity and extract release were determined and compared between the extract incorporated in the electrospun fiber mats and in the cast films. Poly(vinyl alcohol) (PVA) was selected as the polymer matrix. Extracts in the amount of 2.5%, 5%, and 10% w/w, based on the weight of PVA, were incorporated with 10% w/w PVA to finally obtain electrospun fiber mats and cast films. The extract content was evaluated by antioxidative activity using the 2,2-diphenyl-1-picryhydrazyl (DPPH) method. The morphology of the electrospun fiber mats was analyzed using a scanning electron microscope (SEM). The results showed that the diameters of the fibers were in nanoscales and that no crystal of the extract was found at any concentration of the extract. The extract contents in the electrospun fiber mats prepared at 2.5%, 5%, and 10% w/w of the extract were 9.6%, 9.7%, and 10.8% of the initial loading concentration, respectively, whereas, those in the cast films were 23.9%, 14.5%, and 21.0%, respectively. The release of the extract from the electrospun fiber mats prepared at 2.5%, 5%, and 10% w/w of the extract at 120 min were 73.2%, 83.6%, and 81.3% w/w, respectively. However, much slower release from the cast films was observed (i.e., 4.3%, 29.1%, and 40.8% w/w, respectively).

  1. Cellulose nanowhiskers extracted from TEMPO-oxidized jute fibers.

    PubMed

    Cao, Xinwang; Ding, Bin; Yu, Jianyong; Al-Deyab, Salem S

    2012-10-01

    Cellulose nanowhiskers is a kind of renewable and biocompatible nanomaterials evoke much interest because of its versatility in various applications. Here, for the first time, a novel controllable fabrication of cellulose nanowhiskers from jute fibers with a high yield (over 80%) via a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)/NaBr/NaClO system selective oxidization combined with mechanical homogenization is reported. The versatile jute cellulose nanowhiskers with ultrathin diameters (3-10 nm) and high crystallinity (69.72%), contains C6 carboxylate groups converted from C6 primary hydroxyls, which would be particularly useful for applications in the nanocomposites as reinforcing phase, as well as in tissue engineering, pharmaceutical and optical industries as additives.

  2. High performance carbon fibers from mesophases produced by supercritical fluid extraction

    NASA Astrophysics Data System (ADS)

    Dauche, Franck Michel

    The purpose of this research is to investigate the potential of supercritical fluid extraction for the production of an improved precursor for the manufacture of high thermal conductivity carbon fibers. Mesophase pitch fractions were produced by the continuous fractionation of an isotropic petroleum-based pitch with supercritical toluene in a region of liquid-liquid equilibrium. A statistical experimental design was used to investigate a region of extraction operating conditions from which the fractions were expected to exhibit superior spinnability. Chemical and physical characterizations were performed on the fractions, and the results were used to explore the effect of the extraction conditions on the mesophase properties. DRIFT data were shown to be particularly useful for characterizing the chemical composition of the mesophase fractions produced, and GPC was successfully used to determine their molecular weight distribution. Two thermodynamic models based on the SAFT equation together with (1) the concepts of continuous thermodynamics (2) molecular weight information on the oligomeric nature of the feed pitch were used to correlate the measured results. By using three adjustable parameters, solvent compositions and molecular weight distributions in each phase were calculated. Although the oligomeric model is able to qualitatively represent trends observed in the data, it cannot as yet be used to quantitatively predict phase compositions. Based on the characterizations of the supercritically extracted mesophases produced, selected fractions were melt-spun into round- and ribbon-shaped fibers using a laboratory-scale melt-spinning apparatus. It was found that a relatively narrow window of mesophase properties and compositions allowed fiber making without off-gassing. For a given spinnable mesophase, wide angle X-ray diffraction was used on as-spun fibers produced over a wide range of spinning temperatures to evaluate their potential to yield, after proper heat

  3. A novel approach for electromembrane extraction based on the use of silver nanometallic-decorated hollow fibers.

    PubMed

    Ramos-Payán, María; Fernández-Torres, Rut; Pérez-Bernal, Juan Luis; Callejón-Mochón, Manuel; Bello-López, Miguel Ángel

    2014-11-07

    A novel approach based on the use of nanometallic-decorated hollow fibers to assist electromembrane extraction is proposed. Microporous polypropylene hollow fibers, on which nanometallic silver was deposited, have been used for the first time as liquid membrane support in electromembrane extraction (EME). Different methods for the generation/deposition of silver nanoparticles (AgNPs) were studied. The best results were obtained with chemical reduction of silver nitrate using NaBH4 in aqueous solution followed by direct deposition on the hollow fibers. The extraction performance of the new supports was compared with a previously developed EME procedure used for the extraction of selected non-steroidal anti-inflammatory drugs (NSAIDs), resulting in an increase in the extraction ratio by a factor of 1.2-2 with a 30% reduction in the extraction time. The new nanometallic-decorated supports open new possibilities for EME due to the singular properties of nanometallic particles, including chemical fiber functionalization.

  4. Theoretical analysis of copper-ion extraction through hollow fiber supported liquid membranes

    SciTech Connect

    Shiau, C.Y.; Chen, P.Z. )

    1993-10-01

    An understanding of the extraction of metal ions through hollow fiber supported liquid membranes is important for the design of such systems. In this paper, copper-ion extraction through hollow fiber supported liquid membranes containing D2EHPA as a carrier agent is analyzed. Both a rigorous model and a simple model with varied permeation coefficients for the system are proposed. The once-through mode is first modeled and the parametric effects on the extraction rate are discussed. The recycling mode is then modeled. A comparison between the rigorous model and the simple model with varied/constant permeation coefficients is made. From the models it is found that the permeation coefficient is a function of copper ion concentration. 18 refs., 9 figs., 1 tab.

  5. Subfrequency noise signal extraction in fiber-optic strain sensors using postprocessing.

    PubMed

    Lam, Timothy T-Y; Gray, Malcolm B; Shaddock, Daniel A; McClelland, David E; Chow, Jong H

    2012-06-01

    Laser frequency fluctuations typically limit the performance of high-resolution interferometric fiber strain sensors. Using time delay interferometry, we demonstrate a frequency noise immune fiber sensing system, where strain signals were extracted well below the noise floor normally imposed by the frequency fluctuations of the laser. Initial measurements show a reduction in the noise floor by a factor of 30, with strain sensitivities of a nanostrain/Hz at 100 mHz and reaching 100 ps/Hz at 1 Hz. Further characterization of the system indicates the potential for at least 4.5 orders of magnitude frequency fluctuation rejection.

  6. Tapered undulator for SASE FELs

    SciTech Connect

    Fawley, William M.; Huang, Zhirong; Kim, Kwang-Je; Vinokurov, Nikolai A.

    2001-09-14

    We discuss the use of tapered undulators to enhance the performance of free-electron lasers (FELs) based upon self-amplified spontaneous emission (SASE), where the radiation tends to have a relatively broad bandwidth, limited temporal phase coherence, and large amplitude fluctuations. Using the polychromatic FEL simulation code GINGER, we numerically demonstrate the effectiveness of a tapered undulator for parameters corresponding to the existing Argonne low-energy undulator test line (LEUTL) FEL. We also study possible tapering options for proposed x-ray FELs such as the Linac Coherent Light Source (LCLS).

  7. Tapered undulators for SASE FELs

    NASA Astrophysics Data System (ADS)

    Fawley, William M.; Huang, Zhirong; Kim, Kwang-Je; Vinokurov, Nikolai A.

    2002-05-01

    We discuss the use of tapered undulators to enhance the performance of free-electron lasers (FELs) based upon self-amplified spontaneous emission, where the radiation tends to have a relatively broad bandwidth and limited temporal coherence. Using the polychromatic FEL simulation code GINGER, we numerically demonstrate the effectiveness of tapered undulators for parameters corresponding to the Argonne low-energy undulator test line FEL and the proposed linac coherent light source.

  8. Fiber

    MedlinePlus

    ... it can help with weight control. Fiber aids digestion and helps prevent constipation . It is sometimes used ... fiber attracts water and turns to gel during digestion. This slows digestion. Soluble fiber is found in ...

  9. Spectro-Perfectionism: An Algorithmic Framework for Photon Noise-Limited Extraction of Optical Fiber Spectroscopy

    NASA Astrophysics Data System (ADS)

    Bolton, Adam S.; Schlegel, David J.

    2010-02-01

    We describe a new algorithm for the “perfect” extraction of one-dimensional (1D) spectra from two-dimensional (2D) digital images of optical fiber spectrographs, based on accurate 2D forward modeling of the raw pixel data. The algorithm is correct for arbitrarily complicated 2D point-spread functions (PSFs), as compared to the traditional optimal extraction algorithm, which is only correct for a limited class of separable PSFs. The algorithm results in statistically independent extracted samples in the 1D spectrum, and preserves the full native resolution of the 2D spectrograph without degradation. Both the statistical errors and the 1D resolution of the extracted spectrum are accurately determined, allowing a correct χ2 comparison of any model spectrum with the data. Using a model PSF similar to that found in the red channel of the Sloan Digital Sky Survey spectrograph, we compare the performance of our algorithm to that of cross-section based optimal extraction, and also demonstrate that our method allows coaddition and foreground estimation to be carried out as an integral part of the extraction step. This work demonstrates the feasibility of current and next-generation multifiber spectrographs for faint-galaxy surveys even in the presence of strong night-sky foregrounds. We describe the handling of subtleties arising from fiber-to-fiber cross talk, discuss some of the likely challenges in deploying our method to the analysis of a full-scale survey, and note that our algorithm could be generalized into an optimal method for the rectification and combination of astronomical imaging data.

  10. Designing a gel-fiber composite to extract nanoparticles from solution

    NASA Astrophysics Data System (ADS)

    Liu, Ya; Kuksenok, Olga; Balazs, Anna

    Using DPD simulations, we proposed the design of a gel-fiber coating where the components of the system act in concert to extract particles from solution and localize these solids in the underlying gel layer. We model an array of flexible fibers that are embedded in a lower critical solution temperature (LCST) thermo-responsive gel, which swells at lower temperatures and collapses at higher temperatures. The system is immersed in a solution containing dispersed nanoparticles and this fluid is driven to flow by an imposed shear. When the gel is heated, it collapses to expose the fibers, and thereby, triggers the ``catch'' process. Namely, the fibers can act like ``arms'' that wrap around the nanoparticle and bring it from the outer solvent into the gel layer. Moreover, we show that depending on the flexibility and hydrophobicity of the fibers, as well as the imposed shear, we can position the nanoparticles at the desired height within the gel layer. Our approach can be utilized for the detection and separation of components in fluids and for the controlled insertion of nanoparticles within a hydrogel at a particular distance from the gel interface

  11. Evaluation of heat extraction through sapphire fibers for the GW observatory KAGRA

    NASA Astrophysics Data System (ADS)

    Khalaidovski, A.; Hofmann, G.; Chen, D.; Komma, J.; Schwarz, C.; Tokoku, C.; Kimura, N.; Suzuki, T.; Scheie, A. O.; Majorana, E.; Nawrodt, R.; Yamamoto, K.

    2014-05-01

    Currently, the Japanese gravitational wave laser interferometer KAGRA is under construction in the Kamioka mine. As one main feature, it will employ sapphire mirrors operated at a temperature of 20 K to reduce the impact from thermal noise. To reduce seismic noise, the mirrors will also be suspended from multi-stage pendulums. Thus the heat load deposited in the mirrors by absorption of the circulating laser light as well as heat load from thermal radiation will need to be extracted through the last suspension stage. This stage will consist of four thin sapphire fibers with larger heads necessary to connect the fibers to both the mirror and the upper stage. In this paper, we discuss heat conductivity measurements on different fiber candidates. While all fibers had a diameter of 1.6 mm, different surface treatments and approaches to attach the heads were analyzed. Our measurements show that fibers fulfilling the basic KAGRA heat conductivity requirement of κ ⩾ 5000 W m-1 K-1 at 20 K are technologically feasible.

  12. Spectral tuning of a locally bent microfiber taper interferometer with a nanosized liquid crystal overlay.

    PubMed

    Luo, Haimei; Wang, Changjing; Ji, Yinghua; Yuan, Wen; Zhang, Guoping; Wang, Yifan; Hong, Zehua; Wang, Xianping

    2016-09-10

    In this paper, the tuning characteristics of locally bent microfiber taper covered with a nanosized high-refractive-index liquid crystal (LC) layer under different temperatures and electric field intensities have been theoretically analyzed and experimentally investigated. A locally bent microfiber taper interferometer with a waist diameter of ∼3.72  μm is fabricated by using the flame brushing technique, followed by bending the transition region of the taper to form a modal interferometer and later by placing a ∼200  nm LC layer over the uniform taper waist region. Experimental results indicate that a high-efficiency thermal or electric tuning of an LC-coated locally bent microfiber taper interferometer could be achieved. This suggests a potential application of this device as tunable all-fiber photonic devices, such as filters, modulators, and sensing elements.

  13. A microsphere-taper cascading structured microfiber for temperature sensing

    NASA Astrophysics Data System (ADS)

    Xian, Pei; Feng, Guoying; Zhou, Shouhuan

    2016-04-01

    We propose and demonstrate a technique for cascading a microsphere and an abrupt taper together in a standard singlemode fiber. The proposed microsphere-taper cascading structured microfiber (MTCSM) was fabricated by fusion splicing and electric-arc discharge. Exposing the MTCSM segment to increasing temperatures results in a significant shift of the transmission notches towards longer wavelengths with a slope of approximately 17.24 pm/°C∇ from 35°C to 170°C, and the linearity is 99.8%. Due to its compact size and all-fiber configuration, the proposed sensor has advantages of good mechanical strength, simplicity and low-cost fabrication, such new device would find potential applications in communication and sensing fields.

  14. Comparative evaluation of apically extruded debris with V-Taper, ProTaper Next, and the Self-adjusting File systems

    PubMed Central

    Vyavahare, Nishant K.; Raghavendra, Srinidhi Surya; Desai, Niranjan N.

    2016-01-01

    Background: Complete cleaning of the root canal is the goal for ensuring success in endodontics. Removal of debris plays an important role in achieving this goal. In spite of advancements in instrument design, apical extrusion of debris remains a source of inflammation in the periradicular region. Aim: To comparatively evaluate the amount of apically extruded debris with V-Taper, ProTaper Next, and the self-adjusting File (SAF) system. Materials and Methods: Sixty-four extracted human mandibular teeth with straight root canals were taken. Access openings were done and working length determined. The samples were randomly divided into three groups: Group I - V-Taper files (n = 20), Group II - ProTaper Next (n = 20), Group III - SAF (n = 20). Biomechanical preparation was completed and the debris collected in vials to be quantitatively determined. The data obtained was statistically analyzed using ANOVA and post hoc Tukey's test. Results: All the specimens showed apical debris extrusion. SAF showed significantly less debris extrusion compared to V-Taper and ProTaper Next (P < 0.001). Among Groups I and II, ProTaper Next showed lesser debris extrusion as compared to V-Taper, but it was not significant (P = 0.124). Conclusion: The SAF showed least amount of apical debris extrusion when compared to newer rotary endodontic instruments. This indicates that the incidence of inter-treatment flare-ups due to debris extrusion would be less with the SAF. PMID:27217636

  15. Enhanced Trace-Fiber Color Discrimination by Electrospray Ionization Mass Spectrometry: A Quantitative and Qualitative Tool for the Analysis of Dyes Extracted from Sub-millimeter Nylon Fibers

    SciTech Connect

    2002-09-26

    The application of electrospray-ionization mass spectrometry (ESI-MS) to trace-fiber color analysis is explored using acidic dyes commonly employed to color nylon-based fibers, as well as extracts from dyed nylon fibers. Qualitative information about constituent dyes and quantitative information about the relative amounts of those dyes present on a single fiber become readily available using this technique. Sample requirements for establishing the color-identity of different samples (i.e., comparative trace-fiber analysis) are shown to be sub-millimeter. Absolute verification of dye-mixture identity (beyond the comparison of molecular weights derived from ESI-MS) can be obtained by expanding the technique to include tandem mass spectrometry (ESI-MS/MS). For dyes of unknown origin, the ESI-MS/MS analyses may offer insights into the chemical structure of the compound--information not available from chromatographic techniques alone. This research demonstrates that ESI-MS is viable as a sensitive technique for distinguishing dye constituents extracted from a minute amount of trace fiber evidence. A protocol is suggested to establish/refute the proposition that two fibers--one of which is available in minute quantity only--are of the same origin.

  16. Safer DNA extraction from plant tissues using sucrose buffer and glass fiber filter.

    PubMed

    Takakura, Koh-Ichi; Nishio, Takayuki

    2012-11-01

    For some plant species, DNA extraction and downstream experiments are inhibited by various chemicals such as polysaccharides and polyphenols. This short communication proposed an organic-solvent free (except for ethanol) extraction method. This method consists of an initial washing step with STE buffer (0.25 M sucrose, 0.03 M Tris, 0.05 M EDTA), followed by DNA extraction using a piece of glass fiber filter. The advantages of this method are its safety and low cost. The purity of the DNA solution obtained using this method is not necessarily as high as that obtained using the STE/CTAB method, but it is sufficient for PCR experiments. These points were demonstrated empirically with two species, Japanese speedwell and common dandelion, for which DNA has proven difficult to amplify via PCR in past studies.

  17. Numerical modeling of mode-locked fiber lasers with a fiber-based saturable-absorber

    NASA Astrophysics Data System (ADS)

    Wang, Long; Chong, Andy; Haus, Joseph W.

    2017-01-01

    We report fiber laser simulations with a fiber compatible, self-focusing, saturable absorber (SA) device. The SA device consists of two tapered fiber ends separated by a bulk, nonlinear medium. An optical beam transmitted from one tapered fiber end, propagate through the nonlinear medium (chalcogenide glass As40 S e60) and couples back into the other tapered fiber end. Pulse propagation in the fiber laser cavity is performed using the Split Step Method. Stable pulses are generated with energies around 0.3 nJ and a transform limited pulse width around 200 fs.

  18. Modification and characterization of cellulose cotton fibers for fast extraction of some precious metal ions.

    PubMed

    Monier, M; Akl, M A; Ali, Wael M

    2014-05-01

    In this work, native cellulose cotton fibers were first modified through graft copolymerization of polyacrylonitrile (PAN) and then by insertion of phenyl thiosemicarbazide moieties to finally produce C-PTS chelating fibers, which were fully characterized using various instrumental techniques such as SEM, FTIR, EDX and XRD spectra. The obtained C-PTS were employed in removal and extraction of Au(3+), Pd(2+) and Ag(+) precious metal ions from their aqueous solutions using batch experiments. The kinetic studies showed that the pseudo-second-order model exhibited the best fit for the experimental data. In addition, the adsorption isotherm studies indicated that the adsorption follows the Langmuir model and the maximum adsorption capacities for Au(3+), Pd(2+) and Ag(+) were 198.31, 87.43 and 71.14 mg/g respectively.

  19. Kinetics of Moisture Absorption for Alkali Extracted Steam-Exploded Fiber Filled High-Density Polyethylene Composites

    SciTech Connect

    Taib, R. M.; Ramarad, S.; Ishak, Z. A. M.; Rozman, H. D.

    2010-03-11

    Acacia mangium wood fiber derived from steam-explosion and fiber fractionation treatment was used as fillers for high-density polyethylene (HDPE). The alkali extracted steam-exploded fibers (AEF) obtained were acetylated to produce acetylated fibers (AAEF) having three different weight percent gain (WPG). Composites of AEF or AAEF and HDPE were prepared via 2-roll mill, compression molded and cut into dumbbell specimens. All samples were immersed in water at room temperature for 30 days. The process of absorption of water by all composites followed the kinetics and mechanisms described by the Fick's theory. Diffusion coefficient (D) values increased with filler loading but decreased with increasing WPG of the AAEF fiber. Further decrease was observed when maleated polyethylene (MAPE) was added to the composite system. This was due to improved fiber-matrix adhesion that restricts movement of water molecules from further penetrate inside the composite structures.

  20. Kinetics of Moisture Absorption for Alkali Extracted Steam-Exploded Fiber Filled High-Density Polyethylene Composites

    NASA Astrophysics Data System (ADS)

    Taib, R. M.; Ramarad, S.; Ishak, Z. A. M.; Rozman, H. D.

    2010-03-01

    Acacia mangium wood fiber derived from steam-explosion and fiber fractionation treatment was used as fillers for high-density polyethylene (HDPE). The alkali extracted steam-exploded fibers (AEF) obtained were acetylated to produce acetylated fibers (AAEF) having three different weight percent gain (WPG). Composites of AEF or AAEF and HDPE were prepared via 2-roll mill, compression molded and cut into dumbbell specimens. All samples were immersed in water at room temperature for 30 days. The process of absorption of water by all composites followed the kinetics and mechanisms described by the Fick's theory. Diffusion coefficient (D) values increased with filler loading but decreased with increasing WPG of the AAEF fiber. Further decrease was observed when maleated polyethylene (MAPE) was added to the composite system. This was due to improved fiber-matrix adhesion that restricts movement of water molecules from further penetrate inside the composite structures.

  1. Evaluation of Ultrasonic Fiber Structure Extraction Technique Using Autopsy Specimens of Liver

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Tadashi; Hirai, Kazuki; Yamada, Hiroyuki; Ebara, Masaaki; Hachiya, Hiroyuki

    2005-06-01

    It is very important to diagnose liver cirrhosis noninvasively and correctly. In our previous studies, we proposed a processing technique to detect changes in liver tissue in vivo. In this paper, we propose the evaluation of the relationship between liver disease and echo information using autopsy specimens of a human liver in vitro. It is possible to verify the function of a processing parameter clearly and to compare the processing result and the actual human liver tissue structure by in vitro experiment. In the results of our processing technique, information that did not obey a Rayleigh distribution from the echo signal of the autopsy liver specimens was extracted depending on changes in a particular processing parameter. The fiber tissue structure of the same specimen was extracted from a number of histological images of stained tissue. We constructed 3D structures using the information extracted from the echo signal and the fiber structure of the stained tissue and compared the two. By comparing the 3D structures, it is possible to evaluate the relationship between the information that does not obey a Rayleigh distribution of the echo signal and the fibrosis structure.

  2. Hollow fiber-stir bar sorptive extraction and microwave assisted derivatization of amino acids in biological matrices.

    PubMed

    Li, Jia; Qi, Huan-Yang; Wang, Yan-Bin; Su, Qiong; Wu, Shang; Wu, Lan

    2016-11-25

    A kind of solid phase microextraction configuration combining the principles of hollow fiber solid phase microextraction (HF-SPME) and stir bar sorptive extraction (SBSE) is presented. The main feature of HF-SBSE is the use of microporous hollow fiber acting as the carrier and filter, while a thin stainless steel wire and silica microspheres in the lumen of hollow fiber respectively acting as the magnetic stirrer and the dispersed sorbents for the collection and extraction of the target analytes, thus affording extraction process like SBSE. Moreover, the prepared hollow fiber stir bar was applied to direct microextraction and microwave assisted derivatization with N,O-Bis(trimethylsilyl)trifluroacetamide (BSTFA) of four amino acids in rats' urine and cerebrospinal fluid followed by gas chromatography mass spectrometric analysis. The limits of detection for four amino acids were found to be in the range of 0.0003-0.017μgmL(-1), and all the analytes did not exhibit any lack of fit. The extraction recoveries using HF-SBSE techniques ranged from 71.8% to 102.3%. The results indicated that hollow fiber stir bar sorptive extraction was a promising technique for the enrichment and direct derivatization of analytes extracted from biological matrices without sample clean-up.

  3. Solid-Phase Extraction of Sulfur Mustard Metabolites Using an Activated Carbon Fiber Sorbent.

    PubMed

    Lee, Jin Young; Lee, Yong Han

    2016-01-01

    A novel solid-phase extraction method using activated carbon fiber (ACF) was developed and validated. ACF has a vast network of pores of varying sizes and microporous structures that result in rapid adsorption and selective extraction of sulfur mustard metabolites according to the pH of eluting solvents. ACF could not only selectively extract thiodiglycol and 1-methylsulfinyl-2-[2-(methylthio)-ethylsulfonyl]ethane eluting a 9:1 ratio of dichloromethane to acetone, and 1,1'-sulfonylbis[2-(methylsulfinyl)ethane] and 1,1'-sulfonylbis- [2-S-(N-acetylcysteinyl)ethane] eluting 3% hydrogen chloride in methanol, but could also eliminate most interference without loss of analytes during the loading and washing steps. A sample preparation method has been optimized for the extraction of sulfur mustard metabolites from human urine using an ACF sorbent. The newly developed extraction method was applied to the trace analysis of metabolites of sulfur mustard in human urine matrices in a confidence-building exercise for the analysis of biomedical samples provided by the Organisation for the Prohibition of Chemical Weapons.

  4. Immunomodulatory activity of Bengkoang (Pachyrhizus erosus) fiber extract in vitro and in vivo.

    PubMed

    Kumalasari, Ika Dyah; Nishi, Kosuke; Harmayani, Eni; Raharjo, Sri; Sugahara, Takuya

    2014-01-01

    Bengkoang (Pachyrhizus erosus (L.) Urban) is one of the most popular edible root vegetables in Indonesia. Bengkoang contains fairly large amounts of carbohydrates and crude fiber. The purpose of this research is to evaluate the immunomodulatory effect of the bengkoang fiber extract (BFE) in vitro and in vivo. BFE was prepared by heating the powder of bengkoang fiber suspended in distilled water at 121 °C for 20 min. BFE facilitated IgM production by the human hybridoma cell line HB4C5 cells. In addition, production of IgM, IgG, and IgA by mouse primary splenocytes was facilitated by BFE in a dose-dependent manner. BFE also significantly facilitated production of both interleukin-5 and interleukin-10 by splenocytes. Immunoglobulin production by lymphocytes from the spleen, Peyer's patch, and mesenteric lymph node were significantly activated by oral administration of BFE to mice for 14 days. The serum immunoglobulin levels of IgG, IgM, and IgA were also significantly enhanced. Furthermore, cytokine production by lymphocytes from the spleen, Peyer's patch, and mesenteric lymph node were also facilitated by oral administration of BFE. These results suggest that BFE has positive effects on the immune system in vitro and in vivo.

  5. On-line extraction and determination of two herbicides: comparison between two modes of three-phase hollow fiber microextraction.

    PubMed

    Tajik, Mohammad; Yamini, Yadollah; Esrafili, Ali; Ebrahimpour, Behnam

    2015-02-01

    Two different modes of three-phase hollow fiber liquid-phase microextraction were studied for the extraction of two herbicides, bensulfuron-methyl and linuron. In these two modes, the acceptor phases in the lumen of the hollow fiber were aqueous and organic solvents. The extraction and determination were performed using an automated hollow fiber microextraction instrument followed by high-performance liquid chromatography. For both three-phase hollow fiber liquid-phase microextraction modes, the effect of the main parameters on the extraction efficiency were investigated and optimized by central composite design. Under optimal conditions, both modes showed good linearity and repeatability, but the three-phase hollow fiber liquid-phase microextraction based on two immiscible organic solvents has a better extraction efficiency and figures of merit. The calibration curves for three-phase hollow fiber liquid-phase microextraction with an organic acceptor phase were linear in the range of 0.3-200 and 0.1-150 μg/L and the limits of detection were 0.1 and 0.06 μg/L for bensulfuron-methyl and linuron, respectively. For the conventional three-phase hollow fiber liquid-phase microextraction, the calibration curves were linear in the range of 3.0-250 and 15-400 μg/L and LODs were 1.0 and 5.0 μg/L for bensulfuron-methyl and linuron, respectively. The real sample analysis was carried out by three-phase hollow fiber liquid phase microextraction based on two immiscible organic solvents because of its more favorable characteristics.

  6. Corrosion-resistant steel fiber produced by the melt-extraction method and its use in refractories

    NASA Astrophysics Data System (ADS)

    Van I-Kho; Ven-Nen, Lyu

    1992-09-01

    Corrosion-resistant steel fiber produced by the melt-extraction method has distinct reinforcing properties, a high capacity to bond with a refractory, low net-cost, and economic production. The introduction of corrosion-resistant steel fibers in refractory articles and materials for concrete spraying improves their thermal stability and mechanical strength. The service life of refractory articles is increased as a result of an increase in resistance to failure and impact loads. Use of corrosion-resistant steel fibers contributes to significant material energy savings, and improves the productivity of furnaces and apparatus.

  7. Pulse propagation in the tapered wiggler

    NASA Astrophysics Data System (ADS)

    Al-Abawi, H.; McIver, J. K.; Moore, G. T.; Scully, M. O.

    Theory and preliminary numerical calculations are presented for coherent optical and electron pulse propagation in a free-electron laser with a tapered wiggler. Since only trapped electrons contribute significantly to the laser radiation, it is possible to define generalized 'slow' space-time coordinates in terms of which the electron pulse envelope may be considered constant. The theory is outlined first for the helical wiggler and then is developed for an arbitrary quasiperiodic wiggler, using a more rigorous 'multiple-scaling' approach. In the latter case a modified definition of the electron phase angle is required, and optical harmonic generation is predicted. The numerical calculations show that substantial energy extraction is achievable, but that the optical pulse rapidly breaks up into a series of spikes in the time domain. Surprisingly, the optical spectrum remains quite smooth in appearance.

  8. Vertically-tapered optical waveguide and optical spot transformer formed therefrom

    DOEpatents

    Bakke, Thor; Sullivan, Charles T.

    2004-07-27

    An optical waveguide is disclosed in which a section of the waveguide core is vertically tapered during formation by spin coating by controlling the width of an underlying mesa structure. The optical waveguide can be formed from spin-coatable materials such as polymers, sol-gels and spin-on glasses. The vertically-tapered waveguide section can be used to provide a vertical expansion of an optical mode of light within the optical waveguide. A laterally-tapered section can be added adjacent to the vertically-tapered section to provide for a lateral expansion of the optical mode, thereby forming an optical spot-size transformer for efficient coupling of light between the optical waveguide and a single-mode optical fiber. Such a spot-size transformer can also be added to a III-V semiconductor device by post processing.

  9. Thread gauge for tapered threads

    DOEpatents

    Brewster, Albert L.

    1994-01-11

    The thread gauge permits the user to determine the pitch diameter of tapered threads at the intersection of the pitch cone and the end face of the object being measured. A pair of opposed anvils having lines of threads which match the configuration and taper of the threads on the part being measured are brought into meshing engagement with the threads on opposite sides of the part. The anvils are located linearly into their proper positions by stop fingers on the anvils that are brought into abutting engagement with the end face of the part. This places predetermined reference points of the pitch cone of the thread anvils in registration with corresponding points on the end face of the part being measured, resulting in an accurate determination of the pitch diameter at that location. The thread anvils can be arranged for measuring either internal or external threads.

  10. Thread gauge for tapered threads

    DOEpatents

    Brewster, A.L.

    1994-01-11

    The thread gauge permits the user to determine the pitch diameter of tapered threads at the intersection of the pitch cone and the end face of the object being measured. A pair of opposed anvils having lines of threads which match the configuration and taper of the threads on the part being measured are brought into meshing engagement with the threads on opposite sides of the part. The anvils are located linearly into their proper positions by stop fingers on the anvils that are brought into abutting engagement with the end face of the part. This places predetermined reference points of the pitch cone of the thread anvils in registration with corresponding points on the end face of the part being measured, resulting in an accurate determination of the pitch diameter at that location. The thread anvils can be arranged for measuring either internal or external threads. 13 figures.

  11. Green tea extract decreases muscle pathology and NF-κB immunostaining in regenerating muscle fibers of mdx mice

    PubMed Central

    Evans, Nicholas P.; Call, Jarrod A.; Bassaganya-Riera, Josep; Robertson, John L.; Grange, Robert W.

    2009-01-01

    BACKGROUND & AIMS Duchenne muscular dystrophy is a debilitating genetic disorder characterized by severe muscle wasting and early death in afflicted boys. The primary cause of this disease is mutations in the dystrophin gene resulting in massive muscle degeneration and inflammation. The purpose of this study was to determine if dystrophic muscle pathology and inflammation were decreased by pre-natal and early dietary intervention with green tea extract. METHODS Mdx breeder mice and pups were fed diets containing 0.25% or 0.5% green tea extract and compared to untreated mdx and C57BL/6J mice. Serum creatine kinase was assessed as a systemic indicator of muscle damage. Quantitative histopathological and immunohistochemical techniques were used to determine muscle pathology, macrophage infiltration, and NF-κB localization. RESULTS Early treatment of mdx mice with green tea extract significantly decreased serum creatine kinase by ~85% at age 42 days (P≤0.05). In these mice, the area of normal fiber morphology was increased by as much as ~32% (P≤0.05). The primary histopathological change was a ~21% decrease in the area of regenerating fibers (P≤0.05). NF-κB staining in regenerating muscle fibers was also significantly decreased in green tea extract-treated mdx mice when compared to untreated mdx mice. CONCLUSION Early treatment with green tea extract decreases dystrophic muscle pathology potentially by regulating NF-κB activity in regenerating muscle fibers. PMID:19897286

  12. Fabrication of Optical Fiber Devices

    NASA Astrophysics Data System (ADS)

    Andres, Miguel V.

    In this paper we present the main research activities of the Laboratorio de Fibras Opticas del Instituto de Ciencia de los Materiales de la Universidad de Valencia. We show some of the main results obtained for devices based on tapered fibers, fiber Bragg gratings, acousto-optic effects and photonic crystal fibers.

  13. In Vitro Stimulation of Forage Fiber Degradation by Ruminal Microorganisms with Aspergillus oryzae Fermentation Extract

    PubMed Central

    Varel, Vincent H.; Kreikemeier, Kelly K.; Jung, Hans-Joachim G.; Hatfield, Ronald D.

    1993-01-01

    Aspergillus oryzae fermentation extract (Amaferm) was evaluated for its ability to influence degradation of brome grass and switchgrass fiber fractions by mixed ruminal microorganisms in vitro. Addition of Amaferm at a concentration of 0.067 mg/ml, which is approximately the concentration found in the rumen ecosystem (0.06 mg/ml), increased the degradation of brome grass neutral detergent fiber (NDF) by 28% after fermentation for 12 h (P < 0.01), but had no effect after fermentation for 24 or 48 h. The levels of degradation of both the cellulose and hemicellulose fractions were increased after fermentation for 12 h (P < 0.01). Additions of 0.08 and 8% (vol/vol) Amaferm filtrate (12.5 g/100 ml) stimulated degradation of switchgrass NDF by 12 and 24% (P < 0.01), respectively, after fermentation for 12 h; when 80% filtrate was added, degradation was decreased by 38%. The concentrations of total anaerobes in culture tubes containing 80% filtrate were 5 times greater than the concentrations in the controls; however, the concentrations of cellulolytic organisms were 3.5 times lower than the concentrations in the controls (P < 0.05). These results suggested that the filtrate contained high concentrations of soluble substrate which did not allow the cellulolytic organisms to compete well with other populations. The remaining concentrations of esterified p-coumaric and ferulic acids were lower at 12 h in NDF residues obtained from fermentation mixtures supplemented with Amaferm. Because the total anaerobes were not inhibited in fermentation mixtures containing Amaferm, antibiotics are unlikely to be involved as a mode of action for increasing NDF degradation. The possibility that Amaferm contains enzymes (possibly esterases) that may play a role in stimulating the rate of fiber degradation by mixed ruminal microorganisms by removal of plant cell wall phenolic acid esters is discussed. PMID:16349057

  14. Activation of macrophages stimulated by the bengkoang fiber extract through toll-like receptor 4.

    PubMed

    Kumalasari, Ika Dyah; Nishi, Kosuke; Putra, Agus Budiawan Naro; Sugahara, Takuya

    2014-07-25

    Bengkoang (Pachyrhizus erosus (L.) Urban) is an edible root tuber containing fairly large amounts of carbohydrates and crude fibers. Our previous studies showed that the bengkoang fiber extract (BFE) stimulates activation of macrophages, leading to induction of phagocytotic activity and cytokine production. In the present study we investigated the mechanism underlying activation of murine macrophages by BFE. BFE increased production of TNF-α, IL-6, and nitric oxide by J774.1 cells. In addition BFE also facilitated the gene expression levels of inducible nitric oxide synthase. We examined the effect of a TLR4 inhibitor on cytokine production to investigate the membrane receptor of macrophage activation by BFE. Treatment of J774.1 cells with the TLR4 inhibitor significantly inhibited production of IL-6 and TNF-α, suggesting that TLR4 is the target membrane receptor for BFE. The main signal molecules located downstream of TLR4 such as JNK, p38, ERK, and NF-κB were activated by BFE treatment. The immunostimulatory effect of BFE was cancelled by the pectinase treatment, suggesting that the active ingredient in BFE is pectin-like molecules. Overall results suggested that BFE activates J774.1 cells via the MAPK and NF-κB signaling pathways.

  15. Novel process for the simultaneous extraction and degumming of banana fibers under solid-state cultivation

    PubMed Central

    Jacob, Nicemol; Prema, Parukuttyamma

    2008-01-01

    Various process parameters for the production of polygalacturonase by Streptomyces lydicus under solid-state fermentation were optimized. The optimum particle size of wheat bran for polygalacturonase production was in the range of 500-1000 μm. Initial moisture content of 70% was found to be the optimum for enzyme production. The most suitable inoculum size was 1.25 × 105 CFU/mL and the optimum incubation temperature was 30°C. Addition of carbon sources resulted in 37% increase in enzyme yield (425 U/g), whereas no significant enhancement was obtained on nitrogen supplementation. Maximum enzyme yield was recorded at 72 h. When compared to the initial production medium (108.5 U/g), the enzyme yield was 3.9 fold after optimization. Solid-state fermentation was effectively employed to develop a novel process for the simultaneous extraction and degumming of banana fibers. Streptomyces lydicus was allowed to grow on wheat bran medium in which banana leaf sheath pieces were incorporated and the fiber bundles were separated after a two-step fermentative process. PMID:24031190

  16. The screening method of a bifidogenic dietary fiber extracted from inedible parts of vegetables.

    PubMed

    Iwata, Emiko; Hotta, Hisako; Goto, Masahiro

    2009-08-01

    Total dietary fiber (DF) was extracted from the inedible parts of vegetables such as peel of taro and Chinese yam, pea pod, broad bean pod, and broad bean testa. Effects of these fibers on the growth of bifidobacteria were determined by two kinds of experiments: one was to determine the increase of Bifidobacterium longum JCM1217 (B. longum) in medium containing DF, the other was an in vitro fermentation of the DF by anaerobic slurries of mixed human fecal or rat cecal microbiota. Anaerobic culture was carried out for 48 h in both experiments. In the pure culture of B. longum, the significant increase of bacterial number was observed as compared with 0 h in the medium containing the DF from peel of Chinese yam, pea pod and broad bean pod (p<0.05). On the other hand, bacterial number was decreased in the medium containing the DF from the peel of taro and broad bean testa. We selected the DF from pea pod because of its highest bifidogenic property in human fecal microbiota. In the fermentation of DF from pea pod by rat cecal microbiota, bifidobacteria and lactobacilli were increased. Bacteroidaceae and clostridia were decreased. These results suggested that DF from pea pod had possibility as a prebiotic. The bifidogenic property was affected by the sugar composition of DF.

  17. Flax Fiber Hydrophobic Extract Inhibits Human Skin Cells Inflammation and Causes Remodeling of Extracellular Matrix and Wound Closure Activation

    PubMed Central

    Styrczewska, Monika; Kostyn, Anna; Kulma, Anna; Majkowska-Skrobek, Grazyna; Augustyniak, Daria; Prescha, Anna; Czuj, Tadeusz; Szopa, Jan

    2015-01-01

    Inflammation is the basis of many diseases, with chronic wounds amongst them, limiting cell proliferation and tissue regeneration. Our previous preclinical study of flax fiber applied as a wound dressing and analysis of its components impact on the fibroblast transcriptome suggested flax fiber hydrophobic extract use as an anti-inflammatory and wound healing preparation. The extract contains cannabidiol (CBD), phytosterols, and unsaturated fatty acids, showing great promise in wound healing. In in vitro proliferation and wound closure tests the extract activated cell migration and proliferation. The activity of matrix metalloproteinases in skin cells was increased, suggesting activation of extracellular components remodeling. The expression of cytokines was diminished by the extract in a cannabidiol-dependent manner, but β-sitosterol can act synergistically with CBD in inflammation inhibition. Extracellular matrix related genes were also analyzed, considering their importance in further stages of wound healing. The extract activated skin cell matrix remodeling, but the changes were only partially cannabidiol- and β-sitosterol-dependent. The possible role of fatty acids also present in the extract is suggested. The study shows the hydrophobic flax fiber components as wound healing activators, with anti-inflammatory cannabidiol acting in synergy with sterols, and migration and proliferation promoting agents, some of which still require experimental identification. PMID:26347154

  18. Theory and Simulations of Tapered Diblock Polymers

    NASA Astrophysics Data System (ADS)

    Hall, Lisa M.; Seo, Youngmi; Brown, Jonathan R.

    We study tapered block polymers, AB diblock polymers with a gradient region inserted between the pure A and B blocks such that composition smoothly transitions from A to B (or B to A in the case of inverse tapers). Phase diagrams were created using self consistent field theory (SCFT), and coarse-grained molecular dynamics (MD) simulations were used to study polymer conformations and diffusion, including diffusion of monomer-sized penetrants preferentially dissolved in one of the phases. As has been observed experimentally, we find that tapering makes the A and B blocks more miscible, decreasing domain spacing and shifting the order to disorder transition to lower temperatures. We predict a widening of the bicontinuous double gyroid region of the phase diagram for moderate length normal tapers versus diblocks, suggesting taper length can be used as a control parameter to obtain network phases even at high molecular weight, as may be desirable in transport applications. Additionally, in some inverse tapered systems, SCFT predicts phases not present in the standard AB diblock phase diagram, and MD simulations show how the chains fold back and forth across the interface. In these inverse tapered polymers, as segregation strength is increased, the competing effects of folding and stretching produces lamellae that have domain spacing nearly independent of temperature. We also find that diffusion of penetrants in normal tapers is significantly faster than that in inverse tapers, which is likely related to their unusual conformations. This material is based upon work supported by DOE Grant SC0014209.

  19. PRODUCTION OF FOAMS, FIBERS AND PITCHES USING A COAL EXTRACTION PROCESS

    SciTech Connect

    Chong Chen; Elliot B. Kennel; Liviu Magean; Pete G. Stansberry; Alfred H. Stiller; John W. Zondlo

    2004-06-20

    This Department of Energy National Energy Technology Laboratory sponsored project developed processes for converting coal feedstocks to carbon products, including coal-derived pitch, coke foams and fibers based on solvent extraction processes. A key technology is the use of hydrogenation accomplished at elevated temperatures and pressures to obtain a synthetic coal pitch. Hydrogenation, or partial direct liquefaction of coal, is used to modify the properties of raw coal such that a molten synthetic pitch can be obtained. The amount of hydrogen required to produce a synthetic pitch is about an order of magnitude less than the amount required to produce synthetic crude oil. Hence the conditions for synthetic pitch production consume very little hydrogen and can be accomplished at substantially lower pressure. In the molten state, hot filtration or centrifugation can be used to separate dissolved coal chemicals from mineral matter and insolubles (inertinite), resulting in the production of a purified hydrocarbon pitch. Alternatively, if hydrogenation is not used, aromatic hydrocarbon liquids appropriate for use as precursors to carbon products can obtained by dissolving coal in a solvent. As in the case for partial direct liquefaction pitches, undissolved coal is removed via hot filtration or centrifugation. Excess solvent is boiled off and recovered. The resultant solid material, referred to as Solvent Extracted Carbon Ore or SECO, has been used successfully to produce artificial graphite and carbon foam.

  20. Supercritical fluid extraction: Preparing a superior mesophase precursor for carbon fibers. Final report

    SciTech Connect

    Thies, M.C.

    1994-08-01

    Supercritical fluid (SCF) extraction is being investigated for the production of mesophase pitch, the liquid-crystalline precursor for the manufacture of high-performance carbon fibers. The mesophase pitch is produced by fractionation of an isotropic petroleum pitch with supercritical toluene in a region of liquid-liquid equilibrium that exists at pressures above 40 bar. Dramatic improvements in the reliability of the apparatus have recently been made, and mesophase pitch can now be produced on a routine basis. An experimental program was conducted to explore the effects of temperature, solvent-to-pitch (S/P) ratio, and solvent solubility parameter on the properties of the mesophase pitch produced. Temperatures of 320 and 360 deg C, solubility parameters of 3.7 and 5.0 (cal/cc)(1/2), and S/P ratios of 2.5 and 3.5 were chosen to conform to a two-level, augmented factorial experiment. A linear model correlated the data to a high degree of certainty. Results indicate that the authors can adjust SCF operating conditions and tailor-make a mesophase pitch for a given end use. They have discovered a semitheoretical method for predicting a priori the softening point and yield of mesophase pitch for a given set of SCF operating conditions. The SCF extraction process can be represented on a pseudoternary phase diagram, and good estimates of product yields and softening points can be made from a limited experimental data measured at other conditions.

  1. [Application in methane extraction of fiber methane monitoring system based on spectral absorption].

    PubMed

    Zhao, Yan-jie; Wang, Chang; Liu, Tong-yu; Wang, Zhe; Wei, Yu-bin; Li, Yan-fang; Shang, Ying; Wang, Qian

    2010-10-01

    An optical fiber distributed multi-point methane real-time monitoring system based on the methane spectral absorption characteristic is researched, and it's application in methane extraction is presented. An 1665 nm distributed feedback (DFB) laser is used as the light source by taking the triangular signal to modulate the light frequency of the DFB laser. Using the combination of single-chip computer C8051F410, A/D transform circuit, communication circuit, display circuit, etc, the concentration of methane can be monitored and displayed on the screen. And the function of sounding the alarm bell and communication are achieved. The laser wavelength shift is carried out with adaptive adjustment by the built-in gas calibration pond so as to realize the locking of a methane absorption line. Several field tests have been founded at home and abroad. The results show that the system has good performance in stability and sensitivity. The distributed multi-point methane concentration monitoring is realized in the range of 0%-100%. A sensitivity of ppm order of magnitude has been achieved. It possesses of wide application in methane extraction.

  2. Giant birefringence and tunable differential group delay in Bragg reflector based on tapered three-dimensional hollow waveguide

    NASA Astrophysics Data System (ADS)

    Kumar, Mukesh; Sakagichi, Takahiro; Koyama, Fumio

    2009-02-01

    A tunable Bragg reflector based on a tapered three-dimensional (3D) hollow waveguide (HWG) with variable taper angle has been proposed and demonstrated. A large grating coupling coefficient for a large reflection band and a giant birefringence of 0.01 have been achieved by optimizing the structure of the 3D HWG. The large birefringence causes a delay difference between the orthogonal polarizations and the variable taper angle provides tuning in the delay difference. A 13 ps tuning in differential group delay has been reported with a 3 mm long compact device, which can be used for adjustable compensation of polarization mode dispersion in optical fiber links.

  3. Study of the effect of different fiber coatings and extraction conditions on dry cured ham volatile compounds extracted by solid-phase microextraction (SPME).

    PubMed

    Garcia-Esteban, M; Ansorena, D; Astiasarán, I; Ruiz, J

    2004-10-08

    Extraction of dry cured ham volatile compounds by solid-phase microextraction (SPME) was optimized. Different fiber coatings (carboxen/polydimethylsiloxane (CAR/PDMS), divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS), polydimethylsiloxane (PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB)), times of extraction (15, 30, 60min) and sample preparation (ground samples and homogenates with NaCl saturated solution) were assayed. CAR/PDMS and DVB/CAR/PDMS fiber coatings extracted more than 100 volatile compounds and showed the highest area counts for most volatile compounds. CAR/PDMS coating extracted better those compounds whose Kovats index (KI) was lower than 980 (on average) and DVB/CAR/PDMS those with higher KI. Fifteen minutes of extraction provided a volatile compound profile with lower area counts for most compounds and qualitatively different to that obtained with 30 and 60min of extraction. Homogenates gave a different profile compared to ground samples, with lower total counts for most compounds but higher proportion of aldehydes, and presence of several compounds not found in ground samples.

  4. Magnetic field tunability of optical microfiber taper integrated with ferrofluid.

    PubMed

    Miao, Yinping; Wu, Jixuan; Lin, Wei; Zhang, Kailiang; Yuan, Yujie; Song, Binbin; Zhang, Hao; Liu, Bo; Yao, Jianquan

    2013-12-02

    Optical microfiber taper has unique propagation properties, which provides versatile waveguide structure to design the tunable photonic devices. In this paper, the S-tapered microfiber is fabricated by using simple fusion spicing. The spectral characteristics of microfiber taper integrated with ferrofluid under different magnetic-field intensities have been theoretically analyzed and experimentally demonstrated. The spectrum are both found to become highly magnetic-field-dependent. The results indicate the transmission and wavelength of the dips are adjustable by changing magnetic field intensity. The response of this device to the magnetic field intensity exhibits a Langvin function. Moreover, there is a linear relationship between the transmission loss and magnetic field intensity for a magnetic field intensity range of 25 to 200Oe, and the sensitivities as high as 0.13056dB/Oe and 0.056nm/Oe have been achieved, respectively. This suggests a potential application of this device as a tunable all-in-fiber photonic device, such as magneto-optic modulator, filter, and sensing element.

  5. Application of pseudo-emulsion-based hollow fiber strip dispersion for the extraction of p-nitrophenol from aqueous solutions.

    PubMed

    Naidu, Gedela Ashok Kumar; Gupta, Smita; Chakraborty, Mousumi

    2016-11-01

    The extraction of p-nitrophenol (PNP) from aqueous solutions through a pseudo-emulsion hollow fiber strip dispersion (PEHFSD) system was conducted in a microporous hydrophobic polypropylene hollow fiber membrane contactor. For the optimization of the process variables, face-centered central composite design (FCCD) has been used. It was observed that initial feed concentration, carrier composition and stripping phase concentration were the three FCCD factors, which influenced the nitrophenol extraction. Using the optimized process conditions for the separation of PNP, experiments were also performed for the separation of other nitrophenols through PEHFSD system. By the FCCD design and analysis, almost 99% extraction of all three nitrophenols was achieved at optimum conditions. A mass transfer model was also developed and aqueous and membrane resistances were evaluated as 196.46 s cm(-1) and 50.14 s cm(-1), respectively.

  6. Antidepressant, antioxidant and neurotrophic properties of the standardized extract of Cocos nucifera husk fiber in mice.

    PubMed

    Lima, Eliane Brito Cortez; de Sousa, Caren Nádia Soares; Vasconcelos, Germana Silva; Meneses, Lucas Nascimento; E Silva Pereira, Yuri Freitas; Ximenes, Naiara Coelho; Santos Júnior, Manuel Alves; Matos, Natália Castelo Branco; Brito, Rayanne; Miron, Diogo; Leal, Luzia Kalyne Almeida Moreira; Macêdo, Danielle; Vasconcelos, Silvânia Maria Mendes

    2016-07-01

    The plant Cocos nucifera and its derivatives have shown antidepressant-like effects, although its hydroalcoholic extract has not been studied with this end in mind. Therefore, we decided to determine the antidepressant-like effects of the standardized hydroalcoholic extract of Cocos nucifera husk fiber (HECN) as well as oxidative alterations in the prefrontal cortex (PFC), hippocampus (HC) and striatum (ST), and the levels of brain-derived neurotrophic factor (BDNF) in the HC of mice. The extract was characterized based on the content of total polyphenols as well as two phenol compounds-catechin and chlorogenic acid-by HPLC-PDA. Male animals were treated per os (p.o.) for 7 days with distilled water or HECN (50, 100 or 200 mg/kg), or intraperitoneally with vitamin E (Vit E 400 mg/kg). One hour after the last drug administration, the animals were submitted to the open field test, forced swimming test (FST), tail suspension test (TST) and, immediately after the behavioral tests, had their brain removed for neurochemical determinations. The results showed that HECN100 decreased the immobility time in the FST and TST presenting, thus demonstrating an antidepressant-like effect. The administration of HECN decreased malondialdehyde levels in all doses and brain areas studied with the exception of HECN50 in the HC. The administration of HECN also decreased nitrite levels in all doses and brain regions studied. HECN100 also increased the levels of BDNF in HC of mice. In conclusion, we demonstrated that HECN has antidepressant-like properties, probably based on its antioxidant and neurotrophic effects, and is thus relevant for the treatment of depression.

  7. Model-based optimization of tapered free-electron lasers

    NASA Astrophysics Data System (ADS)

    Mak, Alan; Curbis, Francesca; Werin, Sverker

    2015-04-01

    The energy extraction efficiency is a figure of merit for a free-electron laser (FEL). It can be enhanced by the technique of undulator tapering, which enables the sustained growth of radiation power beyond the initial saturation point. In the development of a single-pass x-ray FEL, it is important to exploit the full potential of this technique and optimize the taper profile aw(z ). Our approach to the optimization is based on the theoretical model by Kroll, Morton, and Rosenbluth, whereby the taper profile aw(z ) is not a predetermined function (such as linear or exponential) but is determined by the physics of a resonant particle. For further enhancement of the energy extraction efficiency, we propose a modification to the model, which involves manipulations of the resonant particle's phase. Using the numerical simulation code GENESIS, we apply our model-based optimization methods to a case of the future FEL at the MAX IV Laboratory (Lund, Sweden), as well as a case of the LCLS-II facility (Stanford, USA).

  8. Design of multiple-ply laminated composite tapered beams

    NASA Technical Reports Server (NTRS)

    Rodriguez, P.

    1993-01-01

    A study of a special case of symmetric laminated composite cantilever beams is presented. The approach models beams that are tapered both in depth and width and investigates the effect of the ply layup angle and the ply taper on bending and interlaminar shearing stresses. For the determination of stresses and deflections, the beam stiffness matrices are expressed as linear functions of the beam length. Using classical lamination theory (CLT) the stiffness matrices are determined and assembled at strategic locations along the length of the beam. They are then inverted and necessary stiffness parameters are obtained numerically and extracted for determination of design information at each location chosen. Several ply layup configurations are investigated, and design considerations are presented based on the findings. Finally, recommendations for the design of these beams are presented, and a means for anticipating the location of highest stresses is offered.

  9. Hollow fiber-based liquid-liquid-liquid micro-extraction with osmosis: I. Theoretical simulation and verification.

    PubMed

    Wu, Qian; Wu, Dapeng; Geng, Xuhui; Shen, Zheng; Guan, Yafeng

    2012-07-27

    Osmosis in hollow fiber-based liquid-liquid-liquid micro-extraction (HF-LLLME) was validated and utilized to improve enrichment factor of extraction in this study. When donor phase (sample solution) with higher ion strength than acceptor phase (extraction phase) was used, osmosis was established from acceptor phase, through organic membrane to donor phase. The mass flux expression of analytes across the organic membrane was established based on the convective-diffusive kinetic model, and the kinetic process for HF-LLLME with osmosis was simulated. Simulation results indicated that osmosis from acceptor phase to donor phase can increase enrichment factor of HF-LLLME, accelerate extraction process, and even result in the distribution ratio of analytes between donor and acceptor phase exceeding their partition coefficient. This phenomenon was verified by the experimental data of extraction with six organic acids and four organic bases as the model analytes.

  10. Extraction and quantification of SO2 content in wines using a hollow fiber contactor.

    PubMed

    Plaza, Andrea; Romero, Julio; Silva, Wladimir; Morales, Elizabeth; Torres, Alejandra; Aguirre, María J

    2014-10-01

    Sulfites [Formula: see text] or sulfur dioxide (SO2) is a preservative widely used in fruits and fruit-derived products. This study aims to propose a membrane contactor process for the selective removal and recovery of SO2 from wines in order to obtain its reliable quantification. Currently, the aspiration and Ripper methods offer a difficult quantification of the sulfite content in red wines because they involve evaporation steps of diluted compounds and a colorimetric assay, respectively. Therefore, an inexpensive and accurate methodology is not currently available for continuous monitoring of SO2 in the liquids food industry. Red wine initially acidified at pH < 1 was treated by membrane extraction at 25 ℃. This operation is based on a hydrophobic Hollow Fiber Contactor, which separates the acidified red wine in the shell side and a diluted aqueous sodium hydroxide solution as receiving solution into the lumenside in countercurrent. Sulfite and bisulfite in the acidified red wine become molecular SO2, which is evaporated through the membrane pores filled with gas. Thus, SO2 is trapped in a colorless solution and the membrane contactor controls its transfer, decreasing experimental error induced in classical methods. Experimental results using model solutions with known concentration values of [Formula: see text] show an average extraction percentage of 98.91 after 4 min. On the other hand, two types of Chilean Cabernet Sauvignon wines were analyzed with the same system to quantify the content of free and total sulfites. Results show a good agreement between these methods and the proposed technique, which shows a lower experimental variability.

  11. Backlight units based on light extraction from a curved optical fiber

    NASA Astrophysics Data System (ADS)

    Fujieda, Ichiro; Arizono, Kazuma; Nishida, Kazuki; Takigawa, Naoki

    2014-06-01

    A backlight unit is constructed by laying out a plastic optical fiber (POF) in a curved trench fabricated in a light-guide plate. First, the light leaks out of the POF at curved sections and enters the plate. Next, the light is extracted from the plate by some microstructures fabricated on the surfaces of the plate. Coupled to a laser diode, its optical power can be efficiently and uniformly delivered over a large area via the POF. In this experiment, we fabricated a 10 cm×10 cm×3 mm prototype unit with off-the-shelf components. It becomes see-through when the space around the POF is filled with index-matching oil. One can build an arbitrary-shaped planar light source by tiling multiple cells and connecting them by a POF. The light inside the POF is depleted as it propagates downstream. This can be compensated by decreasing the radii of curvature. Microstructures on the light-guide plate can distort the passage of ambient light. For a see-through unit, we can distribute them sparsely and/or use absorbers. A see-through backlight unit is a relatively unexplored device, and it might pave the way for new applications.

  12. Protease and Hemicellulase Assisted Extraction of Dietary Fiber from Wastes of Cynara cardunculus

    PubMed Central

    Santo Domingo, Cinthia; Soria, Marcelo; Rojas, Ana M.; Fissore, Eliana N.; Gerschenson, Lía N.

    2015-01-01

    The action of protease and hemicellulase for the extraction of fractions enriched in soluble fiber from bracts and stems of Cynara cardunculus was evaluated. Using a two-factor simplex design comprising protease amounts of 0–200 μL and hemicellulase amounts of 0–200 mg for 5 g of material, we explored the effect of a 5 h enzymatic treatment at 40 °C on the chemical composition and yield of the fractions isolated. The fractions contained inulin and pectin. In general, the protein, inulin, and polyphenol contents and also the yields were higher for fractions obtained from stems. The most marked effects were observed when enzymes were used at higher concentrations, especially for hemicellulase. The inclusion of a pre-heating step increased the yield and the inulin content for fractions isolated from bracts and stems and decreased the protein and polyphenol contents, and the galacturonic acid for bracts. These fractions, in general, contained the polyphenolic compounds monocaffeoylquinic acid, apigenin, and pinoresinol. PMID:25809605

  13. Frequency coded sensors incorporating tapers

    NASA Technical Reports Server (NTRS)

    Hines, Jacqueline H. (Inventor); Solie, Leland P. (Inventor)

    2010-01-01

    A surface acoustic wave device includes a piezoelectric substrate on which is formed a transducer that generates acoustic waves on the surface of the substrate from electrical waves received by the transducer. The waves are carried along an acoustic track to either a second transducer or a reflector. The transducers or transducer and reflector are formed of subsections that are constructed to operate at mutually different frequencies. The subsections of at least one of the transducers or transducer and reflector are out of alignment with respect to one another relative to the transverse of the propagation direction. The out of aligned subsections provide not only a frequency component but also a time to the signal output signal. Frequency response characteristics are improved. An alternative embodiment provides that the transducers and/or reflectors are continuously tapered instead of having discrete frequency subsections.

  14. Electrospun gelatin fiber mats containing a herbal—Centella asiatica—extract and release characteristic of asiaticoside

    NASA Astrophysics Data System (ADS)

    Sikareepaisan, Panprung; Suksamrarn, Apichart; Supaphol, Pitt

    2008-01-01

    Ultra-fine gelatin (type A, porcine skin, ~180 Bloom) fiber mats containing a methanolic crude extract of Centella asiatica (L.) Urban, a medicinal plant widely known for its traditional medical applications including its wound healing ability, were fabricated, for the first time, from the neat gelatin solution (22% w/v in 70 vol% acetic acid) containing the crude extract (mCA) in various amounts (i.e. 5-30 wt% based on the weight of gelatin powder) by electrospinning. Incorporation of mCA in the neat gelatin solution did not affect both the morphology and the size of the mCA-loaded gelatin fibers, as both of the neat and the mCA-loaded gelatin fibers were smooth and the average diameters of these fibers ranged between 226 and 232 nm. The cross-linked mCA-loaded e-spun gelatin fiber mat from the neat gelatin solution containing 30 wt% of mCA was further investigated for the release characteristic of asiaticoside, identified as the most active compound associated with the healing of wounds, in two different types of releasing medium, i.e. acetate buffer and the buffer containing 10 vol% of methanol, based on the thin-layer chromatography (TLC)-densitometry technique. Based on the unit weight of the actual amount of asiaticoside present in the specimens, the total amount of asiaticoside released from the fiber mat specimens was lower than that from the film counterparts while, based on the unit weight of the specimens, an opposite trend was observed.

  15. Magnetical hollow fiber bar collection of extract in homogenous ionic liquid microextraction of triazine herbicides in water samples.

    PubMed

    Wang, Kun; Jiang, Jia; Kang, Mingqin; Li, Dan; Zang, Shuang; Tian, Sizhu; Zhang, Hanqi; Yu, Aimin; Zhang, Ziwei

    2017-04-01

    The homogeneous ionic liquid microextraction combined with magnetical hollow fiber bar collection was developed for extracting triazine herbicides from water samples. These analytes were separated and determined by high performance liquid chromatography. The triazines were quickly extracted into ionic liquid microdroplets dispersed in solution, and then these microdroplets were completely collected with magnetical hollow fiber bars; the pores of which were impregnated with hydrophobic ionic liquid, which makes the phase separation simplified with no need of centrifugation. Some experimental parameters, such as the type of ionic liquid, ultrasonic immersion time of hollow fiber, pH of sample solution, volume of hydrophilic ionic liquid, amount of ion-pairing agent NH4PF6, NaCl concentration, number of magnetical hollow fiber bar, stirring rate, and collection time were investigated and optimized. When the present method was applied to the analysis of real water samples, the precision and recoveries of six triazine herbicides vary from 0.1 to 9.2% and 73.4 to 118.5%, respectively. The detection limits for terbumeton, ametryn, prometryn, terbutryn, trietazine, and dimethametryn were 0.48, 0.15, 0.15, 0.14, 0.35, and 0.16 μg L(-1), respectively.

  16. Low loss coupling to sub-micron thick rib and nanowire waveguides by vertical tapering.

    PubMed

    Madden, S; Jin, Z; Choi, D; Debbarma, S; Bulla, D; Luther-Davies, B

    2013-02-11

    Highly nonlinear planar glass waveguides have been shown to be useful for all optical signal processing. However, the typical SMF-28 fiber to waveguide coupling loss of ~5dB/end remains a barrier to practical implementation. Low loss coupling to a fiber using vertical tapering of the waveguide film is analyzed for rib and nanowire waveguides and experimentally demonstrated for ribs showing polarization and wavelength independence over >300nm bandwidth. Tapers with essentially zero excess loss led to total losses from the waveguide to fiber core of 1.1dB per facet comprising only material absorption (0.75dB) and mode overlap loss (0.36dB), both of which can be eliminated with improvements to processing and materials.

  17. Effect of lipid extraction methods on total dietary fiber and nonstarch polysaccharide contents of selected nuts and seeds.

    PubMed

    Li, B W; Zhao, Z; Jekot, J J

    1997-01-01

    Three extraction methods were used to remove lipid materials from 8 edible nuts and seeds before analysis for their total dietary fiber (TDF) and nonstarch polysaccharide (NSP) contents. Portions of ground materials were extracted by: n-hexane, followed by 80% methanol, n-hexane-acetic acid (95 + 5, v/v), and supercritical carbon dioxide. Defatted samples were gelatinized in water and incubated with amyloglucosidase; 95% ethanol was added to the hydrolyzates, and the residues were collected on tared glass crucibles. TDF was calculated according to a simplified enzymatic-gravimetric method developed in our laboratory, and NSP was determined as described by Englyst and coworkers. Dietary fiber values obtained with any of the extraction methods range from 3.47 g/100 g for cashews to 28.56 g/100 g for sunflower seeds. Nonstarch polysaccharide values range from 2.43 g/100 g for pecans to 5.56 g/100 g for peanuts. With the exception of sunflower seeds, samples extracted with supercritical carbon dioxide had lower TDF contents but similar amounts of NSP compared with samples extracted by the other 2 methods.

  18. Natural cotton fibers as adsorbent for solid-phase extraction of polycyclic aromatic hydrocarbons in water samples.

    PubMed

    Wang, Jianping; Liu, Shengquan; Chen, Chunyan; Zou, Ying; Hu, Huiping; Cai, Qingyun; Yao, Shouzhuo

    2014-07-21

    A natural material, cotton fiber, has been applied as a solid-phase extraction (SPE) adsorbent for sample preparation for the analysis of polycyclic aromatic hydrocarbons (PAH) in water samples using high-performance liquid chromatography. The cotton fiber was used directly without any chemical modifications, which avoided a complex synthesis process and consumption of a large volume of organic solvent. The conditions affecting the extraction efficiency were optimized to achieve high detection sensitivity, and included elution solvent, ultrasonic elution time, extraction time, sample volume, salt concentration and organic modifier addition. Under the optimal conditions, the detection limits for seven PAH compounds could reach up to 0.1-2.0 ng L(-1). The method accuracy was evaluated using recovery measurements in standard spiked samples and good recoveries of 70.69-110.04% with relative standard deviations of less than 10% have been achieved. Consequently, the method developed was successfully applied for determining PAH in environmental samples: snow water, metal-fabrication factory wastewater and Xiangjiang River water, with PAH contents ranging from 13.2 to 83.1 ng L(-1). Therefore, using cotton fiber as a new SPE adsorbent, was easy to prepare, had a low cost and great reusability, and this implies it is a promising method for sample preparation.

  19. Extraction and HPLC analysis of phenolic compounds in leaves, stalks, and textile fibers of Urtica dioica L.

    PubMed

    Pinelli, Patrizia; Ieri, Francesca; Vignolini, Pamela; Bacci, Laura; Baronti, Silvia; Romani, Annalisa

    2008-10-08

    In the present study the phenolic composition of leaves, stalks, and textile fiber extracts from Urtica dioica L. is described. Taking into account the increasing demand for textile products made from natural fibers and the necessity to create sustainable "local" processing chains, an Italian project was funded to evaluate the cultivation of nettle fibers in the region of Tuscany. The leaves of two nettle samples, cultivated and wild (C and W), contain large amounts of chlorogenic and 2- O-caffeoylmalic acid, which represent 71.5 and 76.5% of total phenolics, respectively. Flavonoids are the main class in the stalks: 54.4% of total phenolics in C and 31.2% in W samples. Anthocyanins are second in quantitative importance and are present only in nettle stalks: 28.6% of total phenolics in C and 24.4% in W extracts. Characterization of phenolic compounds in nettle extracts is an important result with regard to the biological properties (antioxidant and antiradical) of these metabolites for their possible applications in various industrial activities, such as food/feed, cosmetics, phytomedicine, and textiles.

  20. Endfire tapered slot antennas on dielectric substrates

    NASA Technical Reports Server (NTRS)

    Yngvesson, K. S.; Schaubert, D. H.; Korzeniowski, T. L.; Kollberg, E. L.; Thungren, T.

    1985-01-01

    Endfire-tapered slot antennas are suitable for many integrated circuit applications, imaging and phased arrays. An investigation of single elements of such antennas, including slots which are exponentially tapered (Vivaldi), linearly tapered, and constant width. For antennas of all types, a good general agreement is obtained for curves of beamwidth-versus-length, normalized to wavelength, when one compares the data with that for traveling-wave antennas published by Zucker (1961). An important condition for this agreement is that the effective dielectric thickness, defined in the text, is in a certain optimum range. This condition is qualitatively explained in terms of the theory for traveling-wave antennas.

  1. Analysis and Measurement of the Displacement Sensor Based on an Up-tapered Mach—Zehnder Interferometer

    NASA Astrophysics Data System (ADS)

    Wen, Xiao-Dong; Ning, Ti-Gang; You, Hai-Dong; Kang, Ze-Xin; Li, Jing; Li, Chao; Feng, Ting; Yu, Shao-Wei; Jian, Wei

    2014-03-01

    A displacement sensor based on an up-tapered Mach—Zehnder interferometer (MZI) is proposed and demonstrated experimentally. For this purpose, a fiber MZI is fabricated by using a commercial fusion splicer. Then the transmission spectra of the sensors with different middle fiber lengths are measured by bending the MZIs with different movements of the moving stage. The maximum sensitivity of 2.457 nm/mm is achieved while the shifting of the moving stage changes from 3mm to 3.5 mm. Note that this kind of up-taper configuration is strong in strength, easy to fabricate and low in cost.

  2. Preparation and selective recognition of a novel solid-phase microextraction fiber combined with molecularly imprinted polymers for the extraction of parabens in soy sample.

    PubMed

    He, Juan; Chen, Si; Jiang, Yili; Shen, Yanzheng; Zhu, Jing; Wei, Hongliang; Zhang, Hongxia; Lu, Kui

    2012-01-01

    A prepared molecularly imprinted polymer with ethyl p-hydroxybenzoate as template molecule was applied for the first time to a homemade solid-phase microextraction fiber. The molecularly imprinted polymer-coated solid-phase microextraction fiber was characterized by scanning electron microscopy and thermogravimetric analysis. Various parameters were investigated, including extraction temperature, extraction time, and desorption time. Under the optimum extraction conditions, the molecularly imprinted polymer-coated solid-phase microextraction fiber exhibited higher selectivity with greater extraction capacity toward parabens compared with the nonimprinted polymer-coated solid-phase microextraction fiber and commercial fibers. The molecularly imprinted polymer-coated solid-phase microextraction fiber was tested using gas chromatography to determine parabens, including methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, and propyl p-hydroxybenzoate. The linear ranges were 0.01-10 μg/mL with a correlation coefficient above 0.9943. The detection limits (under signal-to-noise ratio of 3) were below 0.30 μg/L. The fiber was successfully applied to the simultaneous analysis of three parabens in spiked soy samples with satisfactory recoveries of 95.48, 97.86, and 92.17%, respectively. The relative standard deviations (n=6) were within 2.83-3.91%. The proposed molecularly imprinted polymer-coated solid-phase microextraction method is suitable for selective extraction and determination of trace parabens in food samples.

  3. Mathematical modeling of liquid/liquid hollow fiber membrane contactor accounting for interfacial transport phenomena: Extraction of lanthanides as a surrogate for actinides

    SciTech Connect

    Rogers, J.D.

    1994-08-04

    This report is divided into two parts. The second part is divided into the following sections: experimental protocol; modeling the hollow fiber extractor using film theory; Graetz model of the hollow fiber membrane process; fundamental diffusive-kinetic model; and diffusive liquid membrane device-a rigorous model. The first part is divided into: membrane and membrane process-a concept; metal extraction; kinetics of metal extraction; modeling the membrane contactor; and interfacial phenomenon-boundary conditions-applied to membrane transport.

  4. Property and Shape Modulation of Carbon Fibers Using Lasers.

    PubMed

    Blaker, Jonny J; Anthony, David B; Tang, Guang; Shamsuddin, Siti-Ros; Kalinka, Gerhard; Weinrich, Malte; Abdolvand, Amin; Shaffer, Milo S P; Bismarck, Alexander

    2016-06-29

    An exciting challenge is to create unduloid-reinforcing fibers with tailored dimensions to produce synthetic composites with improved toughness and increased ductility. Continuous carbon fibers, the state-of-the-art reinforcement for structural composites, were modified via controlled laser irradiation to result in expanded outwardly tapered regions, as well as fibers with Q-tip (cotton-bud) end shapes. A pulsed laser treatment was used to introduce damage at the single carbon fiber level, creating expanded regions at predetermined points along the lengths of continuous carbon fibers, while maintaining much of their stiffness. The range of produced shapes was quantified and correlated to single fiber tensile properties. Mapped Raman spectroscopy was used to elucidate the local compositional and structural changes. Irradiation conditions were adjusted to create a swollen weakened region, such that fiber failure occurred in the laser treated region producing two fiber ends with outwardly tapered ends. Loading the tapered fibers allows for viscoelastic energy dissipation during fiber pull-out by enhanced friction as the fibers plough through a matrix. In these tapered fibers, diameters were locally increased up to 53%, forming outward taper angles of up to 1.8°. The tensile strength and strain to failure of the modified fibers were significantly reduced, by 75% and 55%, respectively, ensuring localization of the break in the expanded region; however, the fiber stiffness was only reduced by 17%. Using harsher irradiation conditions, carbon fibers were completely cut, resulting in cotton-bud fiber end shapes. Single fiber pull-out tests performed using these fibers revealed a 6.75-fold increase in work of pull-out compared to pristine carbon fibers. Controlled laser irradiation is a route to modify the shape of continuous carbon fibers along their lengths, as well as to cut them into controlled lengths leaving tapered or cotton-bud shapes.

  5. Gold-reinforced silver nanoprisms on optical fiber tapers—A new base for high precision sensing

    NASA Astrophysics Data System (ADS)

    Wieduwilt, T.; Zeisberger, M.; Thiele, M.; Doherty, B.; Chemnitz, M.; Csaki, A.; Fritzsche, W.; Schmidt, M. A.

    2016-09-01

    Due to their unique optical properties, metallic nanoparticles offer a great potential for important applications such as disease diagnostics, demanding highly integrated device solutions with large refractive index sensitivity. Here we introduce a new type of monolithic localized surface plasmon resonance (LSPR) waveguide sensor based on the combination of an adiabatic optical fiber taper and a high-density ensemble of immobilized gold-reinforced silver nanoprisms, showing sensitivities up to 900 nm/RIU. This result represents the highest value reported so far for a fiber optic sensor using the LSPR effect and exceeds the corresponding value of the bulk solution by a factor of two. The plasmonic resonance is efficiently excited via the evanescent field of the propagating taper mode, leading to pronounced transmission dips (-20 dB). The particle density is so high (approx. 210 particle/μm2) that neighboring particles are able to interact, boosting the sensitivity, as confirmed by qualitative infinite element simulations. We additionally introduce a qualitative model explaining the interaction of plasmon resonance and taper mode on the basis of light extinction, allowing extracting key parameters of the plasmonic taper (e.g., modal attenuation). Due to the monolithic design and the extremely high sensitivity we expect our finding to be relevant in fields such as biomedicine, disease diagnostics, and molecular sensing.

  6. Tapered plug foam spray apparatus

    NASA Technical Reports Server (NTRS)

    Allen, Peter B. (Inventor)

    1996-01-01

    A two-component foam spray gun is readily disassembled for cleaning. It includes a body (1) with reactant (12, 14) and purge gas (16) inlet ports. A moldable valve packing (32) inside the body has a tapered conical interior surface (142), and apertures which match the reactant ports. A valve/tip (40) has a conical outer surface (48) which mates with the valve packing (32). The valve/tip (40) is held in place by a moldable packing washer (34), held at non-constant pressure by a screw (36, 38). The interior of the valve/tip (40) houses a removable mixing chamber (50). The mixing chamber (50) has direct flow orifices (60) and an auxiliary flow path (58, 60) which ameliorate pressure surges. The spray gun can be disassembled for cleaning without disturbing the seal, by removing the valve/tip (40) to the rear, thereby breaking it free of the conical packing. Rotation of the valve/tip (40) relative to the body (1) shuts off the reactant flow, and starts the purge gas flow.

  7. Treatment of bran containing bread by baking enzymes; effect on the growth of probiotic bacteria on soluble dietary fiber extract in vitro.

    PubMed

    Saarinen, Markku T; Lahtinen, Sampo J; Sørensen, Jens F; Tiihonen, Kirsti; Ouwehand, Arthur C; Rautonen, Nina; Morgan, Andrew

    2012-01-01

    Different ways of treating bran by baking enzymes prior to dough making and the baking process were used to increase the amount of water-soluble dietary fiber (DF) in wheat bread with added bran. Soluble DF was extracted from the bread with water and separated from the digestible material with gastrointestinal tract enzymes and by solvent precipitation. The baking enzyme mixtures tested (xylanase and glucanase/cellulase, with and without lipase) increased the amounts of soluble arabinoxylan and protein resistant to digestion. The isolated fiber was used as a growth substrate for 11 probiotic and intestinal Bifidobacterium strains, for commensal strains of Bacteroides fragilis and Escherichia coli, and for potential intestinal pathogenic strains of E. coli O157:H7, Salmonella typhimurium, and Clostridium perfringens. Fermentation analyses indicated that the tested strains had varying capacity to grow in the presence of the extracted fiber. Of the tested probiotic strains B. longum species generally showed the highest ability to utilize the fiber extracts, although the potential pathogens tested also showed an ability to grow on these fiber extracts. In sum, the enzymes used to improve the baking process for high-fiber bread can also be used to produce in situ soluble fiber material, which in turn can exert prebiotic effects on certain potentially beneficial microbes.

  8. Research News: Emulsion Liquid Membrane Extraction in a Hollow-Fiber Contactor

    NASA Technical Reports Server (NTRS)

    Wiencek, John M.; Hu, Shih-Yao

    2000-01-01

    This article describes how ELMs (emulsion liquid membranes) can be used for extraction. The article addresses the disadvantages of ELM extraction in a stirred contactor, and the advantages of SELMs (supported emulsion liquid membranes). The introduction of the article provides background information on liquid-liquid solvent extraction and dispersion-free solvent extraction.

  9. Saccharification of newspaper waste after ammonia fiber expansion or extractive ammonia

    SciTech Connect

    Montella, Salvatore; Balan, Venkatesh; da Costa Sousa, Leonardo; Gunawan, Christa; Giacobbe, Simona; Pepe, Olimpia; Faraco, Vincenza

    2016-03-02

    Here, the lignocellulosic fractions of municipal solid waste (MSW) can be used as renewable resources due to the widespread availability, predictable and low pricing and suitability for most conversion technologies. In particular, after the typical paper recycling loop, the newspaper waste (NW) could be further valorized as feedstock in biorefinering industry since it still contains up to 70 % polysaccharides. In this study, two different physicochemical methods— ammonia fiber expansion (AFEX) and extractive ammonia (EA) were tested for the pretraetment of NW. Furthermore, based on the previously demonstrated ability of the recombinant enzymes endocellulase rCelStrep, α-larabinofuranosidase rPoAbf and its evolved variant rPoAbf F435Y/Y446F to improve the saccharification of different lignocellulosic pretreated biomasses (such as corn stover and Arundo donax), in this study these enzymes were tested for the hydrolysis of pretreated NW, with the aim of valorizing the lignocellulosic fractions of the MSW. In particular, a mixture of purified enzymes containing cellulases, xylanases and accessory hemicellulases, was chosen as reference mix and rCelStrep and rPoAbf or its variant were replaced to EGI and Larb. The results showed that these enzymatic mixes are not suitable for the hydrolysis of NW after AFEX or EA pretreatment. On the other hand, when the enzymes rCelStrep, rPoAbf and rPoAbf F435Y/Y446F were tested for their effect in hydrolysis of pretreated NW by addition to a commercial enzyme mixture, it was shown that the total polysaccharides conversion yield reached 37.32 % for AFEX pretreated NW by adding rPoAbf to the mix whilst the maximum sugars conversion yield for EA pretreated NW was achieved 40.80 % by adding rCelStrep. The maximum glucan conversion yield obtained (45.61 % for EA pretreated NW by adding rCelStrep to the commercial mix) is higher than or comparable to those reported in recent manuscripts adopting hydrolysis conditions similar to

  10. Saccharification of newspaper waste after ammonia fiber expansion or extractive ammonia

    DOE PAGES

    Montella, Salvatore; Balan, Venkatesh; da Costa Sousa, Leonardo; ...

    2016-03-02

    Here, the lignocellulosic fractions of municipal solid waste (MSW) can be used as renewable resources due to the widespread availability, predictable and low pricing and suitability for most conversion technologies. In particular, after the typical paper recycling loop, the newspaper waste (NW) could be further valorized as feedstock in biorefinering industry since it still contains up to 70 % polysaccharides. In this study, two different physicochemical methods— ammonia fiber expansion (AFEX) and extractive ammonia (EA) were tested for the pretraetment of NW. Furthermore, based on the previously demonstrated ability of the recombinant enzymes endocellulase rCelStrep, α-larabinofuranosidase rPoAbf and its evolvedmore » variant rPoAbf F435Y/Y446F to improve the saccharification of different lignocellulosic pretreated biomasses (such as corn stover and Arundo donax), in this study these enzymes were tested for the hydrolysis of pretreated NW, with the aim of valorizing the lignocellulosic fractions of the MSW. In particular, a mixture of purified enzymes containing cellulases, xylanases and accessory hemicellulases, was chosen as reference mix and rCelStrep and rPoAbf or its variant were replaced to EGI and Larb. The results showed that these enzymatic mixes are not suitable for the hydrolysis of NW after AFEX or EA pretreatment. On the other hand, when the enzymes rCelStrep, rPoAbf and rPoAbf F435Y/Y446F were tested for their effect in hydrolysis of pretreated NW by addition to a commercial enzyme mixture, it was shown that the total polysaccharides conversion yield reached 37.32 % for AFEX pretreated NW by adding rPoAbf to the mix whilst the maximum sugars conversion yield for EA pretreated NW was achieved 40.80 % by adding rCelStrep. The maximum glucan conversion yield obtained (45.61 % for EA pretreated NW by adding rCelStrep to the commercial mix) is higher than or comparable to those reported in recent manuscripts adopting hydrolysis conditions similar to

  11. Effect of chestnut extract and chestnut fiber on viability of potential probiotic Lactobacillus strains under gastrointestinal tract conditions.

    PubMed

    Blaiotta, Giuseppe; La Gatta, Barbara; Di Capua, Marika; Di Luccia, Aldo; Coppola, Raffaele; Aponte, Maria

    2013-12-01

    The main challenge to probiotics, during their passage through the gastrointestinal tract, are the acidic gastric secretions of the stomach, and the bile salts released into the duodenum. The survival of the strains, in this phase, is strongly influenced by the food used for their delivery. This work is part of a project studying the development of novel food processes, based on the use of chestnuts from cultivar "Castagna di Montella". In detail, the effect of indigestible chestnut fiber and of chestnut extract on the viability of selected lactic acid bacteria strains was evaluated. Among 28 cultures, twelve strains were selected, on the basis of tolerance to low pH values and bile salts, and submitted to exposition to simulated gastric or bile juice in presence of chestnut extract with or without immobilization in chestnut fiber. The presence of chestnut extract proved to play a significant role on the gastric tolerance improvement of lactobacilli. The recorded protective effect could not be simply related to the starch or reducing sugars content. RP-HPLC demonstrated that in the chestnut flour, there are one or more hydrophobic peptides or oligopeptides, which specifically offer a marked resistance to simulated gastric juice, albeit present at low concentration. These beneficial effects proved to be dependent by the cultivar used to produce the flour.

  12. Extraction of natural weight shift and foot rolling in gait based on hetero-core optical fiber load sensor

    NASA Astrophysics Data System (ADS)

    Otsuka, Yudai; Koyama, Yuya; Nishiyama, Michiko; Watanabe, Kazuhiro

    2016-03-01

    Gait in daily activity affects human health because it may cause physical problems such as asymmetric pelvis, flat foot and bowlegs. Monitoring natural weight shift and foot rolling on plantar has been employed in order for researchers to analyze gait characteristics. Conventional gait monitoring systems have been developed using camera, acceleration sensor, gyro sensor and electrical load sensors. They have some problems such as limited measurement place, temperature dependence and electric leakage. On the other hand, a hetero-core optical fiber sensor has many advantages such as high sensitivity for macro-bending, light weight sensor element, independency on temperature fluctuations, and no electric contact. This paper describes extraction of natural weight shift and foot rolling for gait evaluation by using a sensitive shoe, in the insole of which hetero-core optical load sensors are embedded for detecting plantar pressure. Plantar pressure of three subjects who wear the sensitive shoe and walk on the treadmill was monitored. As a result, weight shift and foot rolling for three subjects were extracted using the proposed sensitive shoe in terms of centroid movement and positions. Additionally, these extracted data are compared to that of electric load sensor to ensure consistency. For these results, it was successfully demonstrated that hetero-core optical fiber load sensor performed in unconstraint gait monitoring as well as electric load sensor.

  13. Analysis of guided wave propagation in a tapered composite panel

    NASA Astrophysics Data System (ADS)

    Wandowski, Tomasz; Malinowski, Pawel; Moll, Jochen; Radzienski, Maciej; Ostachowicz, Wieslaw

    2015-03-01

    Many studies have been published in recent years on Lamb wave propagation in isotropic and (multi-layered) anisotropic structures. In this paper, adiabatic wave propagation phenomenon in a tapered composite panel made out of glass fiber reinforced polymers (GFRP) will be considered. Such structural elements are often used e.g. in wind turbine blades and aerospace structures. Here, the wave velocity of each wave mode does not only change with frequency and the direction of wave propagation. It further changes locally due to the varying cross-section of the GFRP panel. Elastic waves were excited using a piezoelectric transducer. Full wave-field measurements using scanning Laser Doppler vibrometry have been performed. This approach allows the detailed analysis of elastic wave propagation in composite specimen with linearly changing thickness. It will be demonstrated here experimentally, that the wave velocity changes significantly due to the tapered geometry of the structure. Hence, this work motivates the theoretical and experimental analysis of adiabatic mode propagation for the purpose of Non-Destructive Testing and Structural Health Monitoring.

  14. Comparison of conventional hollow fiber based liquid phase microextraction and electromembrane extraction efficiencies for the extraction of ephedrine from biological fluids.

    PubMed

    Fotouhi, Lida; Yamini, Yadollah; Molaei, Saeideh; Seidi, Shahram

    2011-12-02

    In the present study, hollow fiber liquid phase microextraction (HF-LPME) based on pH gradient and electromembrane extraction (EME) coupled with high-performance liquid chromatography (HPLC) was compared for the extraction of ephedrine from biological samples. The influences of fundamental parameters affecting the extraction efficiency of ephedrine were studied and optimized for both methods. Under the optimized conditions, preconcentration factors of 120 and 35 for urine and 51 and 8 for human plasma were obtained using EME and HF-LPME, respectively. The calibration curves showed good linearity for urine and plasma samples by both methods with the coefficient of estimations higher than 0.98. The limits of detection were obtained 5 and 10 ng mL(-1) using EME and 60 and 200 ng mL(-1) by HF-LPME for urine and plasma samples respectively. The relative standard deviations of the analysis were found in the range of 5.2-8.6% (n=3). The results showed that in comparison with HF-LPME based on pH gradient, EME is a much more effective transport process, providing high extraction efficiencies in very short time.

  15. Training theory and taper: validation in triathlon athletes.

    PubMed

    Banister, E W; Carter, J B; Zarkadas, P C

    1999-01-01

    This paper defines a training theory with which to predict the effectiveness of various formats of taper in optimizing physical performance from a standardized period of training and taper. Four different taper profiles: step reduction vs exponential (exp) decay and fast vs slow exp decay tapers, were simulated in a systems model to predict performance p(t) resulting from a standard square-wave quantity of training for 28 days. The relative effectiveness of each of the profiles in producing optimal physical improvement above pre-taper criterion physical test standards (running and cycle ergometry) was determined. Simulation showed that an exp taper was better than a step-reduction taper, and a fast exp decay taper was superior to a slow exp decay taper. The results of the simulation were tested experimentally in field trials to assess the correspondence between simulation and real-training criterion physical tests in triathlon athletes. The results showed that the exp taper (tau = 5 days) group made a significantly greater improvement above a pre-taper standard (P < or = 0.05) than the step-reduction taper group in cycle ergometry, and was better, but not significantly so, in a 5-km run. A fast exp taper group B (tau = 4 days) performed significantly better (P < or = 0.05) in maximal, cycle ergometry above a pre-taper training standard than a slow exp taper group A (tau = 8 days) and was improved more, but not significantly so, than group A in a 5-km criterion run. The mean improvement on both physical tests by exp decay taper groups all increased significantly (P < or = 0.05) above their pre-taper training standard. Maximum oxygen uptake increased significantly in a group of eight remaining athletes during 2 weeks of final taper after three athletes left early for final preparations at the race site.

  16. Extraction of beta-glucan from oats for soluble dietary fiber quality analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    BACKGROUND: We have tested extraction protocols for soluble ß-glucan in order to optimize conditions for production of ß-glucan solutions for quality evaluation. We applied varied extraction time, temperature, pH, flour/water ratio, number of re-extractions, hydrothermal treatments and tested genoty...

  17. Comparison of two techniques for removing fiber posts.

    PubMed

    Gesi, A; Magnolfi, S; Goracci, C; Ferrari, M

    2003-09-01

    The purpose of this study was to evaluate the time needed to remove several types of fiber posts using two different bur kits. Estimates refer to the time needed to pass the fiber post until arriving at the gutta-percha. Sixty extracted anterior teeth were treated endodontically. A post space with a standard depth of 10 mm was prepared in each root canal. The sample was randomly divided into 3 groups of 20 specimens each. Three different types of posts were cemented: group 1, Conic 6% tapered fiber posts (Ghimas); group 2, FRC Poster fiber posts (Ivoclar-Vivadent); and group 3, Composipost carbon fiber posts (RTD). To remove the post, for half of each group's specimens the burs from the RTD fiber posts removal kit were used (subgroup A). From the other half of the teeth in each group (subgroup B), posts were removed by using a diamond bur and a Largo bur. Composipost carbon fiber posts (group 3) took significantly less time to remove than the other two types of posts (p < 0.05). For the bur kits, the procedure involving the use of a diamond and a Largo bur (subgroup B) was significantly faster (p < 0.05). The interaction between the type of post and the type of bur kit used was not significant (p > 0.05).

  18. Development of SiC Large Tapered Crystal Growth

    NASA Technical Reports Server (NTRS)

    Neudeck, Phil

    2011-01-01

    Research Focus Area: Power Electronics, Temperature Tolerant Devices. Demonstrate initial feasibility of totally new "Large Tapered Crystal" (LTC) process for growing vastly improved large-diameter wide-band gap wafers. Addresses Targets: The goal of this research is to experimentally investigate and demonstrate feasibility of the key unproven LTC growth processes in SiC. Laser-assisted growth of long SiC fiber seeds. Radial epitaxial growth enlargement of seeds into large SiC boules. Uniqueness and Impacts open a new technology path to large-diameter SiC and GaN wafers with 1000-fold defect density improvement at 2-4 fold lower cost. Leapfrog improvement in wide band gap power device capability and cost.

  19. Surface ion-imprinted amino-functionalized cellulosic cotton fibers for selective extraction of Cu(II) ions.

    PubMed

    Monier, M; Ibrahim, Amr A; Metwally, M M; Badawy, D S

    2015-11-01

    Surface ion-imprinted amino-functionalized cellulosic fibers (Cu-ABZ) were manufactured for efficient selective adsorption of Cu(2+) ions. The chemical modification steps had been characterized utilizing elemental analysis; Fourier transforms infrared (FTIR) along with wide angle X-ray diffraction (XRD) spectroscopy. Also, the morphological structure of the ion-imprinted and the non-imprinted (NI-ABZ) fibers were visualized and compared with that of the native cotton fibers using scanning electron microscope (SEM). In addition, the coordination mode by which the Cu(2+) ions bonded to the active sites were examined by both FTIR and X-ray photo electron spectra (XPS). Both Cu-ABZ and NI-ABZ were implemented in batch experiments for optimizing the conditions by which the Cu(2+) ions can be selectively removal from aqueous medium and pH 5 was the optimum for the metal ion extraction. Moreover, the kinetics and isotherm studies revealed that the adsorption data fitted with pseudo-second-order kinetic and Langmuir models with estimated maximum adsorption capacity 93.6mg/g. Also, the reusability studies indicated that the prepared ion-imprinted adsorbent maintains more than 95% of its original activity after fifth generation cycle.

  20. Turbine airfoil fabricated from tapered extrusions

    DOEpatents

    Marra, John J

    2013-07-16

    An airfoil (30) and fabrication process for turbine blades with cooling channels (26). Tapered tubes (32A-32D) are bonded together in a parallel sequence, forming a leading edge (21), a trailing edge (22), and pressure and suction side walls (23, 24) connected by internal ribs (25). The tapered tubes may be extruded without camber to simplify the extrusion process, then bonded along matching surfaces (34), forming a non-cambered airfoil (28), which may be cambered in a hot forming process and cut (48) to length. The tubes may have tapered walls that are thinner at the blade tip (T1) than at the base (T2), reducing mass. A cap (50) may be attached to the blade tip. A mounting lug (58) may be forged (60) on the airfoil base and then machined, completing the blade for mounting in a turbine rotor disk.

  1. Two critical tapers in a single wedge

    NASA Astrophysics Data System (ADS)

    Smit, J.; Burg, J.-P.; Brun, J.-P.

    2009-04-01

    Thrust involving a ductile décollement (e.g. salt, over-pressured shales) like Zagros, Jura, Pakistan Salt Ranges, Cascades and Makran have in common a small cross-sectional taper, attributed to large thrust spacing and fast frontward propagation above the ductile décollement. Such a low cross-sectional taper has been analytically explained by approximating the ductile layer as a horizon with negligible shear strength. We tested the development of thrust wedges involving a ductile basal décollement of uniform shear strength by means of laboratory experiments. The model consists of a sand layer with initial wedge geometry and a basal ductile décollement of constant thickness and shear strength made of silicone putty. 30% of bulk shortening is applied to the wedge at constant velocity. Thrusting starts in the middle of the wedge, followed by in-sequence frontward propagation. The back part of the wedge, between backstop and the closest thrust, remains undeformed; it passively advances over the base without internal deformation. It appears that both domains have different critical tapers. The inner domain is in a critical state from the onset of shortening (i.e. the initial wedge is already critical), while the frontal domain steadily acquires a state of critical taper by thrusting. This result is at variance with the classical assumption that shortening of a wedge made of homogeneous layers creates a single critical taper. The experimental thrust wedges do show other features characteristic for weak décollement wedges like narrow cross-sectional taper, large thrust spacing and variety in thrust geometries. Application of the results to natural thrust wedges like the Jura Mountains could shed new light on their development and geometry at depth.

  2. Stress intensity factor in a tapered specimen

    NASA Technical Reports Server (NTRS)

    Xue-Hui, L.; Erdogan, F.

    1985-01-01

    The general problem of a tapered specimen containing an edge crack is formulated in terms of a system of singular integral equations. The equations are solved and the stress intensity factor is calculated for a compact and for a slender tapered specimen, the latter simulating the double cantilever beam. The results are obtained primarily for a pair of concentrated forces and for crack surface wedge forces. The stress intensity factors are also obtained for a long strip under uniform tension which contains inclined edge cracks.

  3. Linear control of the spectral characteristics of wavelength-selective components with a high-index tapered thin-film planar waveguide and a single-mode half-coupler.

    PubMed

    Das, A K; Hussain, A

    1999-04-20

    A simple system of linearly tunable fiber-film wavelength-dependent components is demonstrated that includes a linearly tapered high-index thin-film planar waveguide (PWG) evanescently coupled by a single-mode-fiber half-coupler. We present experimental and theoretical results for the linear tuning of spectral responses such as coupled power, resonance position (lambda0), and fiber output-light polarization through position shifting of the linearly tapered PWG, in the direction of the propagating light in the fiber, over the half-coupler block. We achieved almost linear control of the spectral response by changing the temperature of mixture-of-oils and overlay-doped poly(methyl methacrylate) PWG's when the refractive index of the system decreases with temperature. The variation in thickness of the tapered film is along the direction of the interaction length of the system. Linear tapered PWG's that comprised a mixture of oils, BK7 glass, and overlay-doped PMMA with high refractive indices were fabricated that could operate the device at lower and higher modes. We investigated the dependence of tuning lambda0 on the PWG mode. Tuning by shifting of a linear tapered PWG over a fiber half-block is mode dependent, whereas tuning by changing the refractive index of a uniform PWG is mode independent. Wavelength shift Deltalambda0 is found to decrease with an increase in the resonant PWG mode number m for linearly tapered PWG's. A fiber-to-asymmetric linear tapered-PWG coupler, which maintains the taper slope to within a specific limit, can function as a linearly tunable polarizer for the light in the fiber.

  4. 77 FR 50716 - Tapered Roller Bearings From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ... COMMISSION Tapered Roller Bearings From China Determination On the basis of the record \\1\\ developed in the... antidumping duty order on tapered roller bearings from China would be likely to lead to continuation or... Publication 4343 (August 2012), entitled Tapered Roller Bearings from China: Investigation No....

  5. Microstrip transmission line tapers on ferrites

    SciTech Connect

    Albuquerque, M.R.; dAssuncao, A.G.; Lima, F.

    1997-04-01

    The spectral domain approach is employed to perform a theoretical investigation of tapered microstrip lines on magnetized ferrite substrates. A linear variation of the conducting strip width along the direction of propagation is considered. The analysis takes into account the effects of the applied dc magnetic bias field in the transmission characteristics of these structures. The properties of the taper are determined by a model based on a segmentation of the considered line into uniform microstrip line subsections. Normalized phase constants and characteristic impedances are obtained by using the Hertz vector potentials method and Galerkin numerical technique. Numerical results are presented to show the taper input parameters as a function of the load impedance, geometrical dimensions, operating frequency, and ferrite parameters, considering the orientation and magnitude changes of the biasing magnetic-field {bold H}{sub 0}. The results agree fairly well with those available in the literature for tapered microstrip lines on isotropic dielectric substrates. {copyright} {ital 1997 American Institute of Physics.}

  6. 60 GHz Tapered Transmission Line Resonators

    DTIC Science & Technology

    2008-09-15

    DARPA TEAM program (contract no. DAAB07-02-1- L428 ), Motorola, and the UC-Micro program. 60 GHz Tapered Transmission Line Resonators by...0403427, wafer fabrication donation by STMicroelectronics, DARPA TEAM program (con- tract no. DAAB07-02-1- L428 ), Motorola, and the UC-Micro program. 1

  7. Tapered LSO arrays for small animal PET

    NASA Astrophysics Data System (ADS)

    Yang, Yongfeng; St. James, Sara; Wu, Yibao; Du, Huini; Qi, Jinyi; Farrell, Richard; Dokhale, Purushottam A.; Shah, Kanai S.; Vaigneur, Keith; Cherry, Simon R.

    2011-01-01

    By using detectors with good depth encoding accuracy (~2 mm), an animal PET scanner can be built with a small ring diameter and thick crystals to simultaneously obtain high spatial resolution and high sensitivity. However, there will be large wedge-shaped gaps between detector modules in such a scanner if traditional cuboid crystal arrays are used in a polygonal arrangement. The gaps can be minimized by using tapered scintillator arrays enabling the sensitivity of the scanner to be further improved. In this work, tapered lutetium oxyorthosilicate (LSO) arrays with different crystal dimensions and different combinations of inter-crystal reflector and crystal surface treatments were manufactured and their performance was evaluated. Arrays were read out from both ends by position-sensitive avalanche photodiodes (PSAPDs). In the optimal configuration, arrays consisting of 0.5 mm LSO elements could be clearly resolved and a depth of interaction resolution of 2.6 mm was obtained for a 20 mm thick array. For this tapered array, the intrinsic spatial is degraded from 0.67 to 0.75 mm compared to a standard cuboidal array with similar dimensions, while the increase in efficiency is 41%. Tapered scintillator arrays offer the prospect of improvements in sensitivity and sampling for small-bore scanners, without large increases in manufacturing complexity.

  8. Morphological and spectroscopic analysis of cellulose nanocrystals extracted from oil palm empty fruit bunch fiber

    SciTech Connect

    Dasan, Y. K. Bhat, A. H.; Faiz, A.

    2015-07-22

    This work evaluates the use of oil palm empty fruit bunch (OPEFB) fiber as a source of cellulose to obtain nanocrystalline cellulose (CNC) by acid hydrolysis reaction. The raw OPEFB fibers were pretreated with aqueous Sodium hydroxide at 80°C followed by bleaching treatment and further hydrolyzed with Sulphuric acid at 45°C with limited range of hydrolysis time and acid concentration. The resulting CNC’s were characterized for spectroscopic, crystallographic and morphological properties using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometer (XRD), Transmission Electron Microscope (TEM) and Atomic Force Microscopy (AFM). Finding of this study shows that the properties of CNC’s are strongly dependent on the hydrolysis time and acid concentration.

  9. Morphological and spectroscopic analysis of cellulose nanocrystals extracted from oil palm empty fruit bunch fiber

    NASA Astrophysics Data System (ADS)

    Dasan, Y. K.; Bhat, A. H.; Faiz, A.

    2015-07-01

    This work evaluates the use of oil palm empty fruit bunch (OPEFB) fiber as a source of cellulose to obtain nanocrystalline cellulose (CNC) by acid hydrolysis reaction. The raw OPEFB fibers were pretreated with aqueous Sodium hydroxide at 80°C followed by bleaching treatment and further hydrolyzed with Sulphuric acid at 45°C with limited range of hydrolysis time and acid concentration. The resulting CNC's were characterized for spectroscopic, crystallographic and morphological properties using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometer (XRD), Transmission Electron Microscope (TEM) and Atomic Force Microscopy (AFM). Finding of this study shows that the properties of CNC's are strongly dependent on the hydrolysis time and acid concentration.

  10. Determination of Carotenoids in Egg Yolk by High Performance Liquid Chromatography with Vortex-Assisted Hollow Fiber Liquid-Phase Microextraction using Mixed Extraction Solvent.

    PubMed

    Wang, Juan; Wu, Nan; Yang, Yaling

    2016-11-01

    A vortex-assisted hollow fiber liquid-phase microextraction method using a mixed solvent as the extraction solvent followed by high performance liquid chromatography diode-array detection was developed for the extraction and determination of two carotenoids including lutein and β-carotene from egg yolk. The method is based on the microextraction of carotenoids from sample solution into extracting agent (20 μL), which is located in the lumen of hollow fiber followed by vortex-mixing. The mixed solvent (1-octanol+1-undecanol, 6:4, v:v) was employed as extracting agent for it has suitable viscosity and compatible with carotenoids via hollow fiber. Vortex-mixing was utilized to provide effective and mild mixing of sample solution and increase the contact between analytes and boundary layers of the hollow fiber. Parameters influencing recoveries were investigated and optimized. Under the optimum conditions, the linear range of lutein and β-carotene were from 50 to 1,000 ng mL(-1) The correlation coefficients of the calibration curves were >0.9982, relative standard deviations (n = 5) were between 2.23% and 3.51% and the limits of detection were 0.038 and 0.045 μg mL(-1) for lutein and β-carotene, respectively. The proposed method was successfully applied to the extraction and determination of caroteonids in egg yolk with the satisfactory relative recoveries (90.2-101.8%).

  11. Single muscle fiber adaptations with marathon training.

    PubMed

    Trappe, Scott; Harber, Matthew; Creer, Andrew; Gallagher, Philip; Slivka, Dustin; Minchev, Kiril; Whitsett, David

    2006-09-01

    The purpose of this investigation was to characterize the effects of marathon training on single muscle fiber contractile function in a group of recreational runners. Muscle biopsies were obtained from the gastrocnemius muscle of seven individuals (22 +/- 1 yr, 177 +/- 3 cm, and 68 +/- 2 kg) before, after 13 wk of run training, and after 3 wk of taper. Slow-twitch myosin heavy chain [(MHC) I] and fast-twitch (MHC IIa) muscle fibers were analyzed for size, strength (P(o)), speed (V(o)), and power. The run training program led to the successful completion of a marathon (range 3 h 56 min to 5 h 35 min). Oxygen uptake during submaximal running and citrate synthase activity were improved (P < 0.05) with the training program. Muscle fiber size declined (P < 0.05) by approximately 20% in both fiber types after training. P(o) was maintained in both fiber types with training and increased (P < 0.05) by 18% in the MHC IIa fibers after taper. This resulted in >60% increase (P < 0.05) in force per cross-sectional area in both fiber types. Fiber V(o) increased (P < 0.05) by 28% in MHC I fibers with training and was unchanged in MHC IIa fibers. Peak power increased (P < 0.05) in MHC I and IIa fibers after training with a further increase (P < 0.05) in MHC IIa fiber power after taper. These data show that marathon training decreased slow-twitch and fast-twitch muscle fiber size but that it maintained or improved the functional profile of these fibers. A taper period before the marathon further improved the functional profile of the muscle, which was targeted to the fast-twitch muscle fibers.

  12. Fourier domain mode-locked swept source at 1050 nm based on a tapered amplifier.

    PubMed

    Marschall, Sebastian; Klein, Thomas; Wieser, Wolfgang; Biedermann, Benjamin R; Hsu, Kevin; Hansen, Kim P; Sumpf, Bernd; Hasler, Karl-Heinz; Erbert, Götz; Jensen, Ole B; Pedersen, Christian; Huber, Robert; Andersen, Peter E

    2010-07-19

    While swept source optical coherence tomography (OCT) in the 1050 nm range is promising for retinal imaging, there are certain challenges. Conventional semiconductor gain media have limited output power, and the performance of high-speed Fourier domain mode-locked (FDML) lasers suffers from chromatic dispersion in standard optical fiber. We developed a novel light source with a tapered amplifier as gain medium, and investigated the FDML performance comparing two fiber delay lines with different dispersion properties. We introduced an additional gain element into the resonator, and thereby achieved stable FDML operation, exploiting the full bandwidth of the tapered amplifier despite high dispersion. The light source operates at a repetition rate of 116 kHz with an effective average output power in excess of 30 mW. With a total sweep range of 70 nm, we achieved an axial resolution of 15 microm in air (approximately 11 microm in tissue) in OCT measurements. As our work shows, tapered amplifiers are suitable gain media for swept sources at 1050 nm with increased output power, while high gain counteracts dispersion effects in an FDML laser.

  13. Use of genetic algorithms to optimize fiber optic probe design for the extraction of tissue optical properties.

    PubMed

    Palmer, Gregory M; Ramanujam, Nirmala

    2007-08-01

    This paper outlines a framework by which the optimal illumination/collection geometry can be identified for a particular biomedical application. In this paper, this framework was used to identify the optimal probe geometry for the accurate determination of tissue optical properties representative of that in the ultraviolet-visible (UV-VIS) spectral range. An optimal probe geometry was identified which consisted of a single illumination and two collection fibers, one of which is insensitive to changes in scattering properties, and the other is insensitive to changes in the attenuation coefficient. Using this probe geometry in conjunction with a neural network algorithm, the optical properties could be extracted with root-mean-square errors of 0.30 cm(-1) for the reduced scattering coefficient (tested range of 3-40 cm(-1)), and 0.41 cm(-1) for the absorption coefficient (tested range of 0-80 cm(-1)).

  14. Chitosan-based microcapsules containing grapefruit seed extract grafted onto cellulose fibers by a non-toxic procedure.

    PubMed

    Alonso, Diana; Gimeno, Miquel; Sepúlveda-Sánchez, José D; Shirai, Keiko

    2010-04-19

    A novel non-toxic procedure is described for the grafting of chitosan-based microcapsules containing grapefruit seed oil extract onto cellulose. The cellulose was previously UV-irradiated and then functionalized from an aqueous emulsion of the chitosan with the essential oil. The novel materials are readily attained with durable fragrance and enhanced antimicrobial properties. The incorporation of chitosan as determined from the elemental analyses data was 16.08+/-0.29 mg/g of sample. Scanning electron microscopy (SEM) and gas chromatography-mass spectroscopy (GC-MS) provided further evidence for the successful attachment of chitosan microcapsules containing the essential oil to the treated cellulose fibers. The materials thus produced displayed 100% inhibition of Escherichia coli and Staphylococcus epidermidis up to 48 h of incubation. Inhibition of bacteria by the essential oil was also evaluated at several concentrations.

  15. Assessment of solid phase microfiber extraction fibers for the monitoring of volatile organoarsinicals emitted from a plant-soil system.

    PubMed

    Ruppert, L; Lin, Z-Q; Dixon, R P; Johnson, K A

    2013-11-15

    Phytoremediation, the use of plants and microbes to clean up inorganic and organic pollutants, has shown great promise as an inexpensive and feasible form of remediation. More recently, studies have shown that some plants have an amazing capacity to volatilize contaminants and can be an effective remediation strategy if the chemicals released are non-toxic. Arsenic contamination and remediation has drawn great attention in the scientific community. However, its toxicity also varies depending on its form. We evaluated, optimized, and then utilized a solid phase microfiber extraction (SPME) head space sampling technique to characterize the organoarsinical emissions from rabbitfoot grass (Polypogon monspeliensis) in arsenic treated soils to determine if the potentially more toxic organic forms of arsenic (AsH3, AsH2CH3, AsH(CH3)2, and As(CH3)3) were being emitted from the plant-soil system. The SPME fiber that proved best fitted for this application was the DVB/CAR/PDMS fiber with a 45 min sampling period. We did detect and confirm the emissions of dimethylchloroarsine (AsCl(CH3)2) and pentamethylarsine (As(CH3)5). However, it was determined that the more toxic organic forms of arsenic were not released during phytovolatilization.

  16. An efficient and cost effective method of RNA extraction from mucilage, phenol and secondary metabolite rich bark tissue of tossa jute (C. olitorius L.) actively developing phloem fiber.

    PubMed

    Choudhary, S B; Kumar, M; Chowdhury, I; Singh, R K; Pandey, S P; Sharma, H K; Karmakar, P G

    2016-06-01

    Tossa jute is an important natural fiber crop of Southeast Asian countries including India, Bangladesh, China, Thailand, Myanmar etc. Traditional industrial application of jute fiber is limited to the packaging products like hessians, sacks, etc. and the fiber found unsuitable for textile industries largely due to significantly high lignin content. Therefore, understanding genetic factors underlying lignin biosynthesis in tossa jute holds promise for jute based product diversification. The major limiting factor in undertaking such study is unavailability of efficient protocol for RNA extraction at secondary growth active stage of tossa jute. Here we report a simplified, swift and cost effective protocol for isolating fairly good quality RNA from bark tissue of 65-days-old field grown tossa jute plant with active secondary growth. The purity, concentration and integrity of extracted RNA ascertained. To confirm downstream amenability, isolated RNA samples were reverse transcribed and PCR analysis done by using CCoAMT1 primer. Results established that method of RNA extraction presented here is an improvement over the other methods, particularly for bark tissue of field grown tossa jute at advance developmental stage. Therefore, present study will enhance our ability to understand expression pattern of fiber formation and maturation related genes in mature bark tissue that holds key for much talked genetic manipulation of fiber quality via lignin optimisation in the crop.

  17. Transverse Emittance Reduction with Tapered Foil

    SciTech Connect

    Jiao, Yi; Chao, Alex; Cai, Yunhai; /SLAC

    2011-12-09

    The idea of reducing transverse emittance with tapered energy-loss foil is proposed by J.M. Peterson in 1980s and recently by B. Carlsten. In this paper, we present the physical model of tapered energy-loss foil and analyze the emittance reduction using the concept of eigen emittance. The study shows that, to reduce transverse emittance, one should collimate at least 4% of particles which has either much low energy or large transverse divergence. The multiple coulomb scattering is not trivial, leading to a limited emittance reduction ratio. Small transverse emittances are of essential importance for the accelerator facilities generating free electron lasers, especially in hard X-ray region. The idea of reducing transverse emittance with tapered energy-loss foil is recently proposed by B. Carlsten [1], and can be traced back to J.M. Peterson's work in 1980s [2]. Peterson illustrated that a transverse energy gradient can be produced with a tapered energy-loss foil which in turn leads to transverse emittance reduction, and also analyzed the emittance growth from the associated multiple coulomb scattering. However, what Peterson proposed was rather a conceptual than a practical design. In this paper, we build a more complete physical model of the tapered foil based on Ref. [2], including the analysis of the transverse emittance reduction using the concept of eigen emittance and confirming the results by various numerical simulations. The eigen emittance equals to the projected emittance when there is no cross correlation in beam's second order moments matrix [3]. To calculate the eigen emittances, it requires only to know the beam distribution at the foil exit. Thus, the analysis of emittance reduction and the optics design of the subsequent beam line section can be separated. In addition, we can combine the effects of multiple coulomb scattering and transverse energy gradient together in the beam matrix and analyze their net effect. We find that,when applied to an

  18. Simultaneous derivatization and extraction of nitrophenols in soil and rain samples using modified hollow-fiber liquid-phase microextraction followed by gas chromatography-mass spectrometry.

    PubMed

    Sobhi, Hamid Reza; Esrafili, Ali; Farahani, Hadi; Gholami, Mitra; Baneshi, Mohammad Mehdi

    2013-11-01

    A simple and sensitive method based on a modified hollow-fiber liquid-phase microextraction followed by gas chromatography-mass spectrometry has been successfully developed for the extraction and simultaneous derivatization of some nitrophenols (NPs) in soil and rain samples. Microwave-assisted solvent extraction was used for the extraction of NPs from the soil, while the rain sample was directly applied to the previously mentioned method. Briefly, in this method, the analytes were extracted from aqueous samples into a thin layer of organic solvent (dodecane + 10% tri-n-octylphosphine oxide) sustained in the pores of a porous hollow fiber. Then, they were back-extracted using a small volume of organic acceptor solution (25 μl; 10 mg/L N-methyl-N-(trimethylsilyl)trifluoroacetamide, as derivatization reagent, in acetonitrile) that was located inside the lumen of the hollow fiber. Under the optimized extraction conditions, enrichment factors of 255 to 280 and limits of detection of 0.1 to 0.2 μg/L (S/N = 3) with dynamic linear ranges of 1-100 μg/L were obtained for the analytes. The accuracy of the approach was tested by the relative recovery experiments on spiked samples, with results ranging from 93 to 113%. The method was shown to be rapid, cost-effective, and potentially interesting for screening purposes.

  19. The Effect of Taper Angle and Spline Geometry on the Initial Stability of Tapered, Splined Modular Titanium Stems.

    PubMed

    Pierson, Jeffery L; Small, Scott R; Rodriguez, Jose A; Kang, Michael N; Glassman, Andrew H

    2015-07-01

    Design parameters affecting initial mechanical stability of tapered, splined modular titanium stems (TSMTSs) are not well understood. Furthermore, there is considerable variability in contemporary designs. We asked if spline geometry and stem taper angle could be optimized in TSMTS to improve mechanical stability to resist axial subsidence and increase torsional stability. Initial stability was quantified with stems of varied taper angle and spline geometry implanted in a foam model replicating 2cm diaphyseal engagement. Increased taper angle and a broad spline geometry exhibited significantly greater axial stability (+21%-269%) than other design combinations. Neither taper angle nor spline geometry significantly altered initial torsional stability.

  20. 980 nm tapered lasers with photonic crystal structure for low vertical divergence

    NASA Astrophysics Data System (ADS)

    Ma, Xiaolong; Qu, Hongwei; Zhao, Pengchao; Liu, Yun; Zheng, Wanhua

    2016-10-01

    High power tapered lasers with nearly diffraction-limited beam quality have attracted much attention in numerous applications such as nonlinear frequency conversion, optical pumping of solid-state and fiber lasers, medical treatment and others. However, the large vertical divergence of conventional tapered lasers is a disadvantage, which makes beam shaping difficult and expensive in applications. Diode lasers with photonic crystal structure can achieve a large mode size and a narrow vertical divergence. In this paper, we present tapered lasers with photonic crystal structure emitting at 980 nm. The epitaxial layer is grown using metal organic chemical vapor deposition. The device has a total cavity length of 2 mm, which consists of a 400-um long ridge-waveguide section and a 1600-um long tapered section. The taper angle is 4°. An output power of 3.3 W is achieved with a peak conversion efficiency of 35% in pulsed mode. The threshold current is 240 mA and the slope efficiency is 0.78 W/A. In continuous wave mode, the output power is 2.87 W, which is limited by a suddenly failure resulting from catastrophic optical mirror damage. The far field divergences with full width at half maximum are 12.3° in the vertical direction and 2.9° in the lateral direction at 0.5 A. At high injection level the vertical divergence doesn't exceed 16°. Beam quality factor M2 is measured based on second moment definition in CW mode. High beam quality is demonstrated by M2 value of less than 2 in both vertical and lateral directions.

  1. Periodically tapered photonic crystal fibre based strain sensor fabricated by a CO2 laser technique

    NASA Astrophysics Data System (ADS)

    Farrell, Gerald; Bo, Lin; Guan, Chunying; Semenova, Yuliya; Wang, Pengfei

    2014-05-01

    A focused CO2 laser beam has been previously used to successfully fabricate both symmetric and asymmetric long period fiber gratings which have been used for a variety of sensing applications. However fabrication by a CO2 laser beam demands a time consuming laser scanning process which increases the difficulty and cost of fabrication. In this paper a fibre sensor based on a fibre heterostructure with a simple configuration consisting of a series of periodical tapers in a photonic crystal fibre (PCF) sandwiched between two singlemode fibres is proposed and investigated experimentally. The tapers are periodically fabricated along the PCF section using a CO2 laser beam. The proposed fibre heterostructure can be used for strain sensing by measuring the wavelength blueshift of the multimode interference dip of the transmission spectrum as a function of strain. An average stain sensitivity of -68.4 pm/μ ɛ has been experimentally achieved over a microstrain range from 0 to 100 μ ɛ. Assuming in practice that the sensor is interrrogated with a ratiometric power measurement system, then the strain resolution is estimated to be better than 1.18×10-2 microstrain. The mechanisms for refractive index modulation periodically tapered PCF under tensile strain measurements are complex but may be regarded as a combination of stress-relaxation and refractive index perturbations over the length of the tapered PCF induced by strain and by tapering. The proposed fibre strain sensor has the advantage of low temperature sensitivity (average 8.4 pm/°C) and an experimental demonstration of this reduced sensitivity is also presented. The proposed strain sensor benefits from simplicity of fabrication and achieves a competitive sensitivity compared with other existing fibre-optic sensors.

  2. Tapered whiskers are required for active tactile sensation

    PubMed Central

    Hires, Samuel Andrew; Pammer, Lorenz; Svoboda, Karel; Golomb, David

    2013-01-01

    Many mammals forage and burrow in dark constrained spaces. Touch through facial whiskers is important during these activities, but the close quarters makes whisker deployment challenging. The diverse shapes of facial whiskers reflect distinct ecological niches. Rodent whiskers are conical, often with a remarkably linear taper. Here we use theoretical and experimental methods to analyze interactions of mouse whiskers with objects. When pushed into objects, conical whiskers suddenly slip at a critical angle. In contrast, cylindrical whiskers do not slip for biologically plausible movements. Conical whiskers sweep across objects and textures in characteristic sequences of brief sticks and slips, which provide information about the tactile world. In contrast, cylindrical whiskers stick and remain stuck, even when sweeping across fine textures. Thus the conical whisker structure is adaptive for sensor mobility in constrained environments and in feature extraction during active haptic exploration of objects and surfaces. DOI: http://dx.doi.org/10.7554/eLife.01350.001 PMID:24252879

  3. Hollow Fiber Supported Liquid Membrane Extraction Combined with HPLC-UV for Simultaneous Preconcentration and Determination of Urinary Hippuric Acid and Mandelic Acid.

    PubMed

    Bahrami, Abdulrahman; Ghamari, Farhad; Yamini, Yadollah; Ghorbani Shahna, Farshid; Moghimbeigi, Abbas

    2017-02-12

    This work describes a new extraction method with hollow-fiber liquid-phase microextraction based on facilitated pH gradient transport for analyzing hippuric acid and mandelic acid in aqueous samples. The factors affecting the metabolites extraction were optimized as follows: the volume of sample solution was 10 mL with pH 2 containing 0.5 mol·L(-1) sodium chloride, liquid membrane containing 1-octanol with 20% (w/v) tributyl phosphate as the carrier, the time of extraction was 150 min, and stirring rate was 500 rpm. The organic phase immobilized in the pores of a hollow fiber was back-extracted into 24 µL of a solution containing sodium carbonate with pH 11, which was placed inside the lumen of the fiber. Under optimized conditions, the high enrichment factors of 172 and 195 folds, detection limit of 0.007 and 0.009 µg·mL(-1) were obtained. The relative standard deviation (RSD) (%) values for intra- and inter-day precisions were calculated at 2.5%-8.2% and 4.1%-10.7%, respectively. The proposed method was successfully applied to the analysis of these metabolites in real urine samples. The results indicated that hollow-fiber liquid-phase microextraction (HF-LPME) based on facilitated pH gradient transport can be used as a sensitive and effective method for the determination of mandelic acid and hippuric acid in urine specimens.

  4. Obtaining Cotton Fiber Length Distribution from Beard Test Method Part 1 - Theoretical Distribution of Cotton Fiber Length

    Technology Transfer Automated Retrieval System (TEKTRAN)

    By testing a tapered fiber beard, certain fiber length parameters can be obtained rapidly. This study is aimed at exploring the possibility to obtain the entire length distribution of a sample from the beard test method. In Part 1, the mathematical function describing cotton fiber length was searc...

  5. Chalcogenide microresonators tailored to distinct morphologies by the shaping of glasses on silica tapers.

    PubMed

    Aktaş, Ozan

    2017-03-01

    Production of chalcogenide (As2Se3) microresonators in sphere, loop, and bottle morphologies by the shaping of glasses at appropriate temperatures between cleaved silica tapers is reported. The quality factors exceed QS=6.2×105, QB=6.7×105, and QL=1.6×104 for the sphere, bottle, and loop microresonators, respectively. All-optical thermally assisted tuning with a rate of 0.61 nm/mW is demonstrated for a bottle microcavity pumped via a silica taper at a wavelength of 670 nm. This technique enables practical and robust in situ production of chalcogenide microresonators thermally spliced to silica fibers in several morphologies with a wide tuning range of size.

  6. Refractometer based on a tapered Mach-Zehnder interferometer with Peanut-Shape structure

    NASA Astrophysics Data System (ADS)

    Huang, Ran; Ni, Kai; Ma, Qifei; Wu, Xueying

    2016-08-01

    A novel refractometer based on tapered Mach-Zehnder modal interferometer (MZI) is proposed and experimentally demonstrated. This sensor is composed of a pair of Peanut-Shape structures and an embedded taper - the former excites high-order cladding modes, while the latter enhances the evanescent field. As the effective refractive index (RI) of cladding is based on the changes of surrounding RI, thus extinction ratio will change due to the alteration of the distribution of power in the fiber which is induced by various differences of core and cladding for RI. As a result, the maximum RI sensitivity of 240.78 extinction ratio/RIU (refractive index unit) is achieved within the range from 1.3334 to 1.4081.

  7. Preparation of solid-phase microextraction fiber coated with single-walled carbon nanotubes by electrophoretic deposition and its application in extracting phenols from aqueous samples.

    PubMed

    Li, Quanlong; Wang, Xuefeng; Yuan, Dongxing

    2009-02-27

    A novel solid-phase microextraction (SPME) Pt fiber coated with single-walled carbon nanotubes (SWCNTs) was prepared by electrophoretic deposition (EPD) and applied to the determination of phenols in aqueous samples by direct immersion (DI)-SPME-HPLC-UV. The results revealed that EPD was a simple and reproducible technique for the preparation of SPME fibers coated with SWCNTs without the use of adhesive. The obtained SWCNT coating did not swell in organic solvents nor strip off from substrate, and possessed high mechanical strength due to the strong Van der Waals attractions between the surfaces of the SWCNTs. The prepared SPME fiber was conductive since both SWCNT coating and Pt wire were conductive. Using Pt wire as substrate, the fiber was unbreakable. Owing to the presence of oxygenated groups on SWCNTs and the high surface area of SWCNTs, the SWCNT fiber was similar to or superior to commercial PA fiber in extracting the studied phenols from aqueous sample. A durability of more than 80 analyses was achieved for one unique fiber. Under optimized conditions, the detection limits for the phenols varied between 0.9 and 3.8 ng/mL, the precisions were in the range of 0.7-3.2% (n=3), and linear ranges were within 10 and 300 ng/mL. The method was successfully applied to the analysis of spiked seawater and tap water samples with the recoveries from 87.5 to 102.0%.

  8. Orthogonal feeding techniques for tapered slot antennas

    NASA Technical Reports Server (NTRS)

    Lee, Richard Q.; Simons, Rainee N.

    1998-01-01

    For array of "brick" configuration there are electrical and mechanical advantages to feed the antenna with a feed on a substrate perpendicular to the antenna substrate. Different techniques have been proposed for exciting patch antennas using such a feed structure.Rncently, an aperture-coupled dielectric resonator antenna using a perpendicular feed substrate has been demonstrated to have very good power coupling efficiency. For a two-dimensional rectangular array with tapered slot antenna elements, a power combining network on perpendicular substrate is generally required to couple power to or from the array. In this paper, we will describe two aperture-coupled techniques for coupling microwave power from a linearly tapered slot antenna (LTSA) to a microstrip feed on a perpendicular substrate. In addition, we will present measured results for return losses and radiation patterns.

  9. Performance of an elliptically tapered neutron guide

    NASA Astrophysics Data System (ADS)

    Mühlbauer, Sebastian; Stadlbauer, Martin; Böni, Peter; Schanzer, Christan; Stahn, Jochen; Filges, Uwe

    2006-11-01

    Supermirror coated neutron guides are used at all modern neutron sources for transporting neutrons over large distances. In order to reduce the transmission losses due to multiple internal reflection of neutrons, ballistic neutron guides with linear tapering have been proposed and realized. However, these systems suffer from an inhomogeneous illumination of the sample. Moreover, the flux decreases significantly with increasing distance from the exit of the neutron guide. We propose using elliptically tapered guides that provide a more homogeneous phase space at the sample position as well as a focusing at the sample. Moreover, the design of the guide system is simplified because ellipses are simply defined by their long and short axes. In order to prove the concept we have manufactured a doubly focusing guide and investigated its properties with neutrons. The experiments show that the predicted gains using the program package McStas are realized. We discuss several applications of elliptic guides in various fields of neutron physics.

  10. Cooling arrangement for a tapered turbine blade

    DOEpatents

    Liang, George

    2010-07-27

    A cooling arrangement (11) for a highly tapered gas turbine blade (10). The cooling arrangement (11) includes a pair of parallel triple-pass serpentine cooling circuits (80,82) formed in an inner radial portion (50) of the blade, and a respective pair of single radial channel cooling circuits (84,86) formed in an outer radial portion (52) of the blade (10), with each single radial channel receiving the cooling fluid discharged from a respective one of the triple-pass serpentine cooling circuit. The cooling arrangement advantageously provides a higher degree of cooling to the most highly stressed radially inner portion of the blade, while providing a lower degree of cooling to the less highly stressed radially outer portion of the blade. The cooling arrangement can be implemented with known casting techniques, thereby facilitating its use on highly tapered, highly twisted Row 4 industrial gas turbine blades that could not be cooled with prior art cooling arrangements.

  11. Spatially resolved spectroscopy using tapered stripline NMR

    NASA Astrophysics Data System (ADS)

    Tijssen, Koen C. H.; Bart, Jacob; Tiggelaar, Roald M.; Janssen, J. W. G. (Hans); Kentgens, Arno P. M.; van Bentum, P. Jan M.

    2016-02-01

    Magnetic field B0 gradients are essential in modern Nuclear Magnetic Resonance spectroscopy and imaging. Although RF/B1 gradients can be used to fulfill a similar role, this is not used in common practice because of practical limitations in the design of B1 gradient coils. Here we present a new method to create B1 gradients using stripline RF coils. The conductor-width of a stripline NMR chip and the strength of its radiofrequency field are correlated, so a stripline chip can be tapered to produce any arbitrary shaped B1 field gradient. Here we show the characterization of this tapered stripline configuration and demonstrate three applications: magnetic resonance imaging on samples with nL-μL volumes, reaction monitoring of fast chemical reactions (10-2-101 s) and the compensation of B0 field gradients to obtain high-resolution spectra in inhomogeneous magnetic fields.

  12. Performance of a tapered pulse tube

    SciTech Connect

    Swift, G.; Allen, M.; Woolan, J.J.

    1998-02-01

    In a well instrumented pulse tube refrigerator having 1,500 W of cooling power at 125 K, the authors have measured the figure of merit of a tapered pulse tube at several operating points. At operating points near the operating point for which the taper was designed, the figure of merit is 0.96. This is close to the theoretical optimum figure of merit 0.97 calculated for this pulse tube considering only two loss mechanisms: heat conduction in the metal pulse tube wall and ordinary thermoacoustic heat transport in the gas within a few thermal penetration depths of the wall. At operating points farther from the design operating point, the measured figure of merit is much lower, as streaming driven convection adds a third loss mechanism.

  13. Selective and simultaneous extractions of Zn and Cu ions by hollow fiber SLM modules containing HEH(EHP) and LIX84

    SciTech Connect

    Lee, J.C.; Jeong, J.; Park, J.T.; Youn, I.J.; Chung, H.S.

    1999-06-01

    The selective extractions of Zn{sup 2+} and Cu{sup 2} from their mixed solutions of sulfate medium have been studied using hollow fiber supported liquid membranes (HFSLM). The HFSLM contained two kinds of extractants; one contained 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester [HEH(EHP)], the commercial name of which is PC88A, for Zn extraction; the other contained the hydroxy oxime reagent LIX84 for Cu extraction. Individuals runs of each HFSLM were made to determine the effect of operational variables on the permeation rates of metal ions and their separation factors. In addition, the simultaneous and selective extractions of both Zn{sup 2+} and Cu{sup 2+} from their mixed solutions were demonstrated using the PC88A and LIX84 HFSLMs together. The performance of simultaneous extraction was compared with those of the individual runs.

  14. Waveguide taper engineering using coordinate transformation technology

    NASA Astrophysics Data System (ADS)

    Tichit, Paul-Henri; Burokur, Shah Nawaz; de Lustrac, André

    2010-01-01

    Spatial coordinate transformation is a suitable tool for the design of complex electromagnetic structures. In this paper, we define three spatial coordinate transformations which show the possibility of designing a taper between two different waveguides. A parametric study is presented for the three transformations and we propose achievable values of permittivity and permeability that can be obtained with existing metamaterials. The performances of such defined structures are demonstrated by finite element numerical simulations.

  15. Waveguide taper engineering using coordinate transformation technology.

    PubMed

    Tichit, Paul-Henri; Burokur, Shah Nawaz; de Lustrac, André

    2010-01-18

    Spatial coordinate transformation is a suitable tool for the design of complex electromagnetic structures. In this paper, we define three spatial coordinate transformations which show the possibility of designing a taper between two different waveguides. A parametric study is presented for the three transformations and we propose achievable values of permittivity and permeability that can be obtained with existing metamaterials. The performances of such defined structures are demonstrated by finite element numerical simulations.

  16. Design of Structurally Efficient Tapered Struts

    NASA Technical Reports Server (NTRS)

    Messinger, Ross

    2010-01-01

    This report describes the analytical study of two full-scale tapered composite struts. The analytical study resulted in the design of two structurally efficient carbon/epoxy struts in accordance with NASA-specified geometries and loading conditions. Detailed stress analysis was performed of the insert, end fitting, and strut body to obtain an optimized weight with positive margins. Two demonstration struts were fabricated based on a well-established design from a previous Space Shuttle strut development program.

  17. Tapered Bottlebrush Polymers: A New Polymer Architecture

    DTIC Science & Technology

    2015-07-30

    length of the backbone polymer . This type of covalent, cone- shaped polymer may have applications in supersoft elastomeric materials and as...rate of polymerization must be as high as possible for the synthesis of precise tapered bottlebrush polymers . An example of the kinetics data obtained... polymers with anchor group 1 allow for faster polymerization . MM Name k p (10 -3 L * mol -1 * s -1 ) t1/2 (s) krel 1S 3k 11 ± 2 68 ± 20

  18. Experimental stiffness of tapered bore seals

    NASA Technical Reports Server (NTRS)

    Fleming, D. P.

    1985-01-01

    The stiffness of tapered-bore ring seals was measured with air as the sealed fluid. Static stiffness agreed fairly well with results of a previous analysis. Cross-coupled stiffness due to shaft rotation was much less than predicted. It is suggested that part of the disparity may be due to simplifying assumptions in the analysis; however, these do not appear to account for the entire difference observed.

  19. Tapered pulse tube for pulse tube refrigerators

    DOEpatents

    Swift, Gregory W.; Olson, Jeffrey R.

    1999-01-01

    Thermal insulation of the pulse tube in a pulse-tube refrigerator is maintained by optimally varying the radius of the pulse tube to suppress convective heat loss from mass flux streaming in the pulse tube. A simple cone with an optimum taper angle will often provide sufficient improvement. Alternatively, the pulse tube radius r as a function of axial position x can be shaped with r(x) such that streaming is optimally suppressed at each x.

  20. Surgical Outcomes of Forearm Loop Arteriovenous Fistula Formation Using Tapered versus Non-Tapered Polytetrafluoroethylene Grafts

    PubMed Central

    Han, Sun; Seo, Pil Won; Ryu, Jae-Wook

    2017-01-01

    Background Tapered grafts, which have a smaller diameter on the arterial side, have been increasingly used for arteriovenous fistula (AVF) formation. We compared the outcomes of 4–6-mm tapered and 6-mm straight forearm loop arteriovenous grafts. Methods A total of 103 patients receiving forearm loop arteriovenous grafts between March 2005 and March 2015 were retrospectively analyzed and separated into 2 groups (group A, 4- to 6-mm tapered grafts, n=78; group B, 6-mm straight grafts, n=25). In each group, complications and patency rates after surgery were assessed. Results Clinical characteristics and laboratory results, except for cerebrovascular disease history (group A, 7.7%; group B, 28.0%; p=0.014), were similar between the groups. No significant differences were found for individual complications. Kaplan-Meier survival analysis revealed no significant differences in 1-year, 3-year, and 5-year patency rates between groups (61.8%, 44.9%, and 38.5% vs. 62.7%, 41.1%, and 35.3%, respectively). Conclusion We found no significant differences in complication and patency rates between the tapered and straight graft groups. If there are no differences in complication and patency between the two graft types, tapered grafts may be a valuable option for AVF formation in light of their other advantages. PMID:28180100

  1. Preparation and evaluation of solid-phase microextraction fibers based on monolithic molecularly imprinted polymers for selective extraction of diacetylmorphine and analogous compounds.

    PubMed

    Djozan, Djavanshir; Baheri, Tahmineh

    2007-09-28

    All of the studies on solid-phase microextraction based on molecularly imprinted polymers up to now have been carried out on the synthesis of the polymer on the surface of the fiber which is brittle and the polymer coating strips during handling. The objective of this study was to develop a method for fabrication of a monolithic and robust solid-phase microextraction fiber on the basis of molecularly imprinted polymer for selective extraction of diacetylmorphine and its structural analogues followed by their GC or GC/MS analysis. A fiber was produced by copolymerization of methacrylic acid-ethylene glycol dimethacrylate imprinted with diacetylmorphine. The effective factors influencing the polymerization have been investigated and are detailed here. Also, the influences of pH, extraction time and temperature on the extraction efficiency of analytes were investigated. The prepared fiber was thermally stable up to 300 degrees C which has vital importance in SPME coupled with GC or GC/MS. The adsorption isotherm modeling was performed by fitting the data of studied compounds to bi-Langmuir isotherm model. The evaluated equilibrium constants for diacetylmorphine were 0.011 and 1824.72 microM(-1), and the number of binding sites was 170.37 and 4.64 nmolg(-1), respectively. This fiber was successfully used for extraction of template molecule from aqueous solution and further analysis with GC or GC/MS. The high extraction efficiency was obtained for diacetylmorphine, 6-monoacetylcodeine, and 6-monoacetylmorphine, yielding the detection limits of 300, 47, and 1 ngmL(-1), respectively.

  2. Monitoring the emission of volatile organic compounds from flowers of Jasminum sambac using solid-phase micro-extraction fibers and gas chromatography with mass spectrometry detection.

    PubMed

    Pragadheesh, Vppalayam Shanmugam; Yadav, Anju; Chanotiya, Chandan Singh; Rout, Prasanta Kumar; Uniyal, Girish Chandra

    2011-09-01

    Solid-phase micro-extraction (SPME) was studied as a solvent free alternative method for the extraction and characterization of volatile compounds in intact and plucked flowers of Jasminum sambac at different day time intervals using gas chromatography (GC-FID) and gas chromatography-quadrupole mass spectrometry. The analytes identified included alcohols, esters, phenolic compounds, and terpenoids. The main constituents identified in the flower aroma using different fibers were cis-3-hexenyl acetate, (E)-beta-ocimene, linalool, benzyl acetate, and (E,E)-alpha-farnesene. The benzyl acetate proportion decreased from morning to afternoon and then increased in evening collections. PDMS fiber showed a high proportion of (E,E)-alpha-farnesene in jasmine floral aroma. Among other constituents identified, cis-3-hexenyl acetate, linalool, and benzyl acetate were major aroma contributors in plucked and living flowers extracts using PDMS/DVB, Carboxen/PDMS, and DVB/Carboxen/PDMS fibers. PDMS/DVB recorded the highest emission for benzyl acetate while the (E)-beta-ocimene proportion was highest in DVB/Carboxen/PDMS when compared with the rest. The highest linalool content, with increasing proportion from morning to noon, was found using mixed coating fibers. Almost negligible volatile adsorption was recorded for the polyacrylate fiber for intact flower aroma, whereas it was most effective for benzyl acetate, followed by indole under plucked conditions. Moreover, the highest amounts extracted, evaluated from the sum of peak areas, were achieved using Carboxen/PDMS, and DVB/Carboxen/PDMS. Introduction of a rapid, and solvent free SPME method for the analysis of multicomponent volatiles can be successfully employed to monitor the extraction and characterization of flower aroma constituents.

  3. Determination of hormones in milk by hollow fiber-based stirring extraction bar liquid-liquid microextraction gas chromatography mass spectrometry.

    PubMed

    Xu, Xu; Liang, Fanghui; Shi, Jiayuan; Zhao, Xin; Liu, Zhuang; Wu, Lijie; Song, Ying; Zhang, Hanqi; Wang, Ziming

    2013-08-06

    The hollow fiber-based stirring extraction bar liquid-liquid microextraction was applied to the extraction of hormones, including 17-α-ethinylestradiol, 17-α-estradiol, estriol, 17-β-estradiol, estrone, 17-α-hydroxyprogesterone, medroxyprogesterone, progesterone and norethisterone acetate, in milk. The present method has the advantages of both hollow fiber-liquid phase microextraction and stirring bar sorptive extraction. The stirring extraction bar was used as both the stirring bar of microextraction, and extractor of the analytes, which can make extraction, clean-up and concentration be carried out in one step. When the extraction was completed, the stirring extraction bar was easy isolated from the extraction system with the magnet. Several experimental parameters, including the type of extraction solvent, the number of hollow stirring extraction bar, extraction time, stirring speed, ionic strength, and desorption conditions were investigated and optimized. The analytes in the extract were derived and determined by gas chromatography mass spectrometry. Under optimal experimental conditions, good linearity was observed in the range of 0.20-20.00ng mL(-1). The limits of detection and quantification were in the range of 0.02-0.06ng mL(-1) and 0.07-0.19ng mL(-1), respectively. The present method was applied to the analysis of milk samples, and the recoveries of analytes were in the range of 93.6-104.6% with the relative standard deviations ranging from 1.6% to 6.2% (n=5). The results showed that the present method was a rapid and feasible method for the determination of hormones in milk samples.

  4. Stress distributions in peri-miniscrew areas from cylindrical and tapered miniscrews inserted at different angles

    PubMed Central

    Choi, Sung-Hwan; Kim, Seong-Jin; Lee, Kee-Joon; Sung, Sang-Jin; Chun, Youn-Sic

    2016-01-01

    Objective The purpose of this study was to analyze stress distributions in the roots, periodontal ligaments (PDLs), and bones around cylindrical and tapered miniscrews inserted at different angles using a finite element analysis. Methods We created a three-dimensional (3D) maxilla model of a dentition with extracted first premolars and used 2 types of miniscrews (tapered and cylindrical) with 1.45-mm diameters and 8-mm lengths. The miniscrews were inserted at 30°, 60°, and 90° angles with respect to the bone surface. A simulated horizontal orthodontic force of 2 N was applied to the miniscrew heads. Then, the stress distributions, magnitudes during miniscrew placement, and force applications were analyzed with a 3D finite element analysis. Results Stresses were primarily absorbed by cortical bone. Moreover, very little stress was transmitted to the roots, PDLs, and cancellous bone. During cylindrical miniscrew insertion, the maximum von Mises stress increased as insertion angle decreased. Tapered miniscrews exhibited greater maximum von Mises stress than cylindrical miniscrews. During force application, maximum von Mises stresses increased in both groups as insertion angles decreased. Conclusions For both cylindrical and tapered miniscrew designs, placement as perpendicular to the bone surface as possible is recommended to reduce stress in the surrounding bone. PMID:27478796

  5. A new generation of spectral extraction and analysis package for Fiber Optics Cassegrain Echelle Spectrograph (FOCES)

    NASA Astrophysics Data System (ADS)

    Wang, Liang; Grupp, Frank; Kellermann, Hanna; Brucalassi, Anna; Schlichter, Jörg; Hopp, Ulrich; Bender, Ralf

    2016-08-01

    We describe a new generation of spectral extraction and analysis software package (EDRS2) for the Fibre Optics Cassegrain Echelle Spectrograph (FOCES), which will be attached to the 2m Fraunhofer Telescope on the Wendelstein Observatory. The package is developed based on Python language and relies on a variety of third party, open source packages such as Numpy and Scipy. EDRS2 contains generalized image calibration routines including overscan correction, bias subtraction, flat fielding and background correction, and can be supplemented by user customized functions to fit other echelle spectrographs. An optimal extraction method is adopted to obtain the one dimensional spectra, and the output multi order, wavelength calibrated spectra are saved in FITS files with binary table format. We introduce the algorithm and performance of major routines in EDRS2.

  6. Fiber Fabry-Perot interferometer with controllable temperature sensitivity.

    PubMed

    Zhang, Xinpu; Peng, Wei; Zhang, Yang

    2015-12-01

    We proposed a fiber taper based on the Fabry-Perot (FP) interferometer structure with controllable temperature sensitivity. The FP interferometer is formed by inserting a segment of tapered fiber tip into the capillary and subsequently splicing the other end of the capillary to a single-mode fiber (SMF), the tapered fiber endface, and the spliced face form the FP cavity. Through controlling the inserted tapered fiber length, a series of FP interferometers were made. Because the inserted taper tip has the degree of freedom along the fiber axial, when the FP interferometer is subjected to temperature variation, the thermal expansion of the fiber taper tip will resist the FP cavity length change caused by the evolution of capillary length, and we can control the temperature sensitivity by adjusting the inserted taper length. In this structure, the equivalent thermal expansion coefficient of the FP interferometer can be defined; it was used to evaluate the temperature sensitivity of the FP interferometer, which provides an effective method to eliminate the temperature effect and to enhance other measurement accuracy. We fabricated the FP interferometers and calibrated their temperature characters by measuring the wavelength shift of the resonance dips in the reflection spectrum. In a temperature range of 50°C to 150°C, the corresponding temperature sensitivities can be controlled between 0 and 1.97 pm/°C when the inserted taper is between 75 and 160 μm. Because of its controllable temperature sensitivity, ease of fabrication, and low cost, this FP interferometer can meet different temperature sensitivity requirements in various application areas, especially in the fields which need temperature insensitivity.

  7. Effects of taper on swim performance. Practical implications.

    PubMed

    Houmard, J A; Johns, R A

    1994-04-01

    Competitive swimmers commonly focus upon optimising performance at a single competition. A period where training volume is incrementally reduced or "tapered" often precedes such a competition. The use of taper is justified as increases in muscular power, and the restoration of plasma haematocrit, haemoglobin and creatine kinase are evident with this training reduction. A consistent performance improvement of approximately 3% has also been reported with taper in competitive swimmers. However, there are limitations in terms of what comprises a successful taper schedule. It appears that a taper which improves performance involves a substantial (60 to 90%) graded reduction in training volume, and daily high intensity interval work over a 7- to 21-day period. Training frequency should be reduced by no more than 50%; a more conservative estimate would be to reduce frequency by approximately 20%. Optimal performance is likely when the reduction in training frequency is combined with the qualitative knowledge of the coach and/or athlete during taper.

  8. Tapering practices of Croatian open-class powerlifting champions.

    PubMed

    Grgic, Jozo; Mikulic, Pavle

    2016-10-27

    The aim of this study was to explore tapering practices among 10 Croatian open-class powerlifting champions (mean ± SD: age 29.2 ± 3.2 years; Wilks coefficient 355.1 ± 54.8). The athletes were interviewed about their tapering practices using a semi-structured interview, after which the audio content was transcribed. The athletes reported decreasing training volume during the taper by 50.5 ± 11.7% using a step type or an exponential type of taper with a fast decay. Training intensity was maintained or increased during the taper, and it reached its highest values 8 ± 3 days before the competition. Training frequency was reduced or maintained during the taper. The final week included a reduction in training frequency by 47.9 ± 17.5% with the last training session performed 3 ± 1 days before the competition. The participants typically stated that the main reasons for conducting the taper were maintaining strength and reducing the amount of fatigue. They also stated that (a) the taper was structured identically for the squat, bench press, and the deadlift; (b) the training during the taper was highly specific, the assistance exercises were removed, and the same equipment was used as during competition; (c) the source of information for tapering was their coach, and training fluctuated based on the coach's feedback; and (d) nutrition, foam rolling, static stretching, and massage were all given extra attention during the taper. These results may aid athletes and coaches in strength sports in terms of the optimization of tapering variables.

  9. Phase Centers of Subapertures in a Tapered Aperture Array.

    SciTech Connect

    Doerry, Armin W.; Bickel, Douglas L.

    2015-11-01

    Antenna apertures that are tapered for sidelobe control can also be parsed into subapertures for Direction of Arrival (DOA) measurements. However, the aperture tapering complicates phase center location for the subapertures, knowledge of which is critical for proper DOA calculation. In addition, tapering affects subaperture gains, making gain dependent on subaperture position. Techniques are presented to calculate subaperture phase center locations, and algorithms are given for equalizing subapertures’ gains. Sidelobe characteristics and mitigation are also discussed.

  10. Removal of Cu(II) and Ni(II) using cellulose extracted from sisal fiber and cellulose-g-acrylic acid copolymer.

    PubMed

    Hajeeth, T; Vijayalakshmi, K; Gomathi, T; Sudha, P N

    2013-11-01

    The extraction of cellulose from sisal fiber was done initially using the steam explosion method. The batch adsorption studies were conducted using the cellulose extracted from the sisal fiber and cellulose-g-acrylic acid as an adsorbent for the removal of Cu(II) and Ni(II) metal ions from aqueous solution. The effect of sorbent amount, agitation period and pH of solution that influence sorption capacity were investigated. From the observed results, it was evident that the adsorption of metal ions increases with the increase in contact time and adsorbent dosage. The optimum pH was found to be 5.0 for the removal of copper(II) and nickel(II) for both the extracted cellulose and cellulose-g-acrylic acid copolymer. The adsorption data were modeled using Langmuir and Freundlich isotherms. The experimental results of the Langmuir, Freundlich isotherms revealed that the adsorption of Cu(II) and nickel(II) ion onto cellulose extracted from the sisal fiber and cellulose-g-acrylic acid copolymer was found to fit well with Freundlich isotherm. The kinetics studies show that the adsorption follows the pseudo-second-order kinetics. From the above results, it was concluded that the cellulose-g-acrylic acid copolymer was found to be an efficient adsorbent.

  11. Rapid determination of 54 pharmaceutical and personal care products in fish samples using microwave-assisted extraction-Hollow fiber-Liquid/solid phase microextraction.

    PubMed

    Zhang, Yi; Guo, Wen; Yue, Zhenfeng; Lin, Li; Zhao, Fengjuan; Chen, Peijin; Wu, Weidong; Zhu, Hong; Yang, Bo; Kuang, Yanyun; Wang, Jiong

    2017-04-15

    In this paper, a simple, rapid, solvent-less and environmental friendliness microextraction method, microwave-assisted extraction-hollow fiber-liquid/solid phase microextraction (MAE-HF-L/SME), was developed for simultaneous extraction and enrichment of 54 trace hydrophilic/lipophilic pharmaceutical and personal care products (PPCPs) from fish samples. A solid-phase extraction material, solid-phase microextraction (SPME) fiber, was synthesized. The SPME fiber had a homogeneous, loose structure and good mechanical properties, and they exhibited a good adsorption capacity for most PPCPs selected. The material formed the basis for the method of MAE-HF-L/SME. A method of liquid chromatography-high resolution mass spectroscopy (LC-HRMS) for analysis of 54 PPCPs. Under optimal synthesis and extraction conditions, the limits of detection (LODs, n=3) and the limits of quantitation (LOQs, n=10) for the 54 PPCPs were between 0.01-0.50μg·kg(-1) and 0.052.00μg·kg(-1), respectively. Percent recoveries and the relative standard deviations (RSDs) in spiked fish samples (n=6) were between 56.3%-119.9% and 0.3%-17.1%, respectively. The microextraction process of 54 PPCPs in MAE-HF-L/SME took approximately 12min. The method has a low matrix interference and high enrichment factor and may be applicable for determination of 54 different PPCPs in fish samples.

  12. Low-crosstalk Si arrayed waveguide grating with parabolic tapers.

    PubMed

    Ye, Tong; Fu, Yunfei; Qiao, Lei; Chu, Tao

    2014-12-29

    A silicon arrayed waveguide grating (AWG) with low channel crosstalk was demonstrated by using ultra-short parabolic tapers to connect the AWG's free propagation regions and single-mode waveguides. The tapers satisfied the requirements of low-loss mode conversion and lower channel crosstalk from the coupling of neighboring waveguides in the AWGs. In this work, three different tapers, including parabolic tapers, linear tapers, and exponential tapers, were theoretically analyzed and experimentally investigated for a comparison of their effects when implemented in AWGs. The experimental results showed that the AWG with parabolic tapers had a crosstalk improvement up to 7.1 dB compared with the others. Based on the advantages of parabolic tapers, a 400-GHz 8 × 8 cyclic AWG with 2.4 dB on-chip loss and -17.6~-25.1 dB crosstalk was fabricated using a simple one-step etching process. Its performance was comparable with that of existing AWGs with bi-level tapers, which require complicated two-step etching fabrication processes.

  13. Radiation pattern analysis of the tapered slot antenna, appendix 1

    NASA Technical Reports Server (NTRS)

    Janaswamy, Ramakrishna

    1986-01-01

    A theoretical model for the tapered slot antenna is presented. The model is valid for any smooth taper of the slot. The problem is solved by modeling the slot electric field and using the half plane Green's function to compute the far fields. The aperture field is obtained by affecting a stepped approximation to the continuous taper and utilizing the uniform wide slot line data. The uniform wide slot line is solved by the spectral Galerkin's technique and closed form experssions are developed for the slot wave length and the slot characteristic impedance. Numerous comparisons with measurement are made to demonstrate the versatility of the model in treating an arbitrary slot taper.

  14. A tapered box model of the cochlea

    NASA Astrophysics Data System (ADS)

    Sun, Luyang; Ni, Guangjian; Elliott, Stephen

    2015-12-01

    The complicated, three dimensional geometry of the fluid chambers in the cochlea is often represented in models of its mechanics by a box with a uniform area along its length. In this paper we use previous measurements of the variation in area of the two fluid chambers along the length of the cochlea in various mammals, to calculate the variation in the "effective area" that determines the 1D fluid coupling, which is given by the harmonic mean of the two chamber areas. The square root of this effective area is found to vary surprisingly linearly along the cochlea length in several mammalian species. This suggests a variation of the box model in which the width and height of the two fluid chambers are still equal, but now decrease linearly along its length. The width of the basilar membrane, BM, is assumed to increase linearly along the length of the model. The analytic form of the 1D fluid pressure distribution due to elemental BM motion is derived for this tapered box model. The added mass due to the near field acoustic coupling can also be computed, which surprisingly turns out to be almost constant along the length of the BM. The coupled response of the box model with a passive BM can then be readily calculated. Although the pressure distributions due to elemental fluid coupling are very different in the uniform and tapered box models, the distribution of the passive BM response in the coupled models are very similar in the two cases, although the overall level of the response in the tapered model is about 10 dB greater than that in the uniform model.

  15. A method to fabricate hemispherical micro-lens of optical fiber

    NASA Astrophysics Data System (ADS)

    Huo, Xin; Pan, Shi

    2008-12-01

    According to the preparation of tapered fiber hemispherical micro-lens by hybrid etching and melting, a geometric calculation model for fabricating hemispherical micro-lens at the end of optical fiber by melting tapered flat fiber end into hemispherical fiber end has been developed. If the taper diameter and taper angle are obtainable, the radius of hemispherical micro-lens of the fiber taper after melting can be calculated. Particularly, hemi-spherical micro-lenses of optical fibers with various radii can be fabricated by etching-cleaving-melting method. According to the linear relationship between etching fiber diameter and etching time, as well as the characteristic of fiber volume maintaining constant before and after electric arc melting, the relationship between the radius of fiber hemispherical micro-lens and etching time was deduced in this paper. Through controlling the etching time precisely after calculating the etching rate, which is determined by the sampling and analysis of the etched fiber, the hemi-spherical micro-lenses with different radius at the fiber ends can be produced. The experiments were conduct to test the operability of this method. The results showed that radii of micro-lenses fabricated by the etching-cleaving-melting method made a good coincidence with the designed radius values of 10µm and 20µm.

  16. Resonant plasmon nanofocusing by closed tapered gaps.

    PubMed

    Søndergaard, Thomas; Bozhevolnyi, Sergey I; Beermann, Jonas; Novikov, Sergey M; Devaux, Eloïse; Ebbesen, Thomas W

    2010-01-01

    We study radiation nanofocusing by closed tapered gaps, i.e. metal V-grooves, under normal illumination, and discover that the local field inside a groove can be resonantly enhanced due to interference of counter-propagating gap plasmons. Considering V-grooves milled in gold, we analyze this phenomenon theoretically, deriving an analytic expression for the resonance condition and predicting more than 550-fold intensity enhancements at resonance, and observe it experimentally with two-photon photoluminescence microscopy, demonstrating more than 100-fold intensity enhancements.

  17. Characterization of angled tapered superluminescent LEDs.

    PubMed

    Causa, Federica; Sarma, Jayanta; Yunus, Sharina

    2002-08-20

    We present a detailed analysis of the output beam of high-power edge-emitting angled tapered superluminescent LEDs (A-TSLEDs). A device model, including spontaneous and stimulated emission processes as well as the typical nonuniform carrier-density distribution due to current spreading and carrier diffusion, has been developed and used to interpret the experimentally obtained characteristics of inhouse-fabricated A-TSLEDs. The good match between measured and theoretical results indicates that the model reproduces the A-TSLED operation very satisfactorily and clearly explains the role of the collecting lens on the pronounced asymmetry of some of the measured optical intensity profiles.

  18. Window taper functions for subaperture processing.

    SciTech Connect

    Doerry, Armin Walter

    2013-12-01

    It is well known that the spectrum of a signal can be calculated with a Discrete Fourier Transform (DFT), where best resolution is achieved by processing the entire data set. However, in some situations it is advantageous to use a staged approach, where data is first processed within subapertures, and the results are then combined and further processed to a final result. An artifact of this approach is the creation of grating lobes in the final response. The nature of the grating lobes, including their amplitude and spacing, is an artifact of window taper functions, subaperture offsets, and subaperture processing parameters. We assess these factors and exemplify their effects.

  19. On the characterization and spinning of solvent extracted lignin towards the manufacture of low-cost carbon fiber

    SciTech Connect

    Baker, Darren A; Gallego, Nidia C; Baker, Frederick S

    2012-01-01

    ABSTRACT: A Kraft hardwood lignin (HWL) and an organic-purified hardwood lignin (HWL-OP) were evaluated as potential precursors for the production of lowcost carbon fibers. It was found that the unpurified HWL exhibited poor spinnability while the HWL-OP exhibited excellent spinnability characteristics. Fibers of various diameters were obtained from the HWL-OP. Thermostabilization studies showed that oxidative stabilization can only be used to convert HWL-OP-based fibers into carbon fibers if extremely low heating rates are applied. Carbonized lignin-based fibers had tensile strength of 0.51 GPa and tensile modulus of 28.6 GPa. VC

  20. Evaluation of the flexural strength of carbon fiber-, quartz fiber-, and glass fiber-based posts.

    PubMed

    Galhano, Graziela Avila; Valandro, Luiz Felipe; de Melo, Renata Marques; Scotti, Roberto; Bottino, Marco Antonio

    2005-03-01

    This study investigated the flexural strength of eight fiber posts (one carbon fiber, one carbon/quartz fiber, one opaque quartz fiber, two translucent quartz fiber, and three glass fiber posts). Eighty fiber posts were used and divided into eight groups (n = 10): G1: C-POST (Bisco); G2: AESTHETI-POST (Bisco); G3: AESTHETI-PLUS (Bisco); G4: LIGHT-POST (Bisco); G5: D.T. LIGHT-POST (Bisco); G6: PARAPOST WHITE (Coltene); G7: FIBERKOR (Pentron); G8: REFORPOST (Angelus). All of the samples were tested using the three-point bending test. The averages obtained were submitted to the ANOVA and to Tukey's test (p < 0.05). The mean values (MPa) of the groups AESTHETI-POST-carbon/quartz fiber post (Bisco) and AESTHETI-PLUS-quartz fiber post (Bisco) were statistically similar and higher than the mean values of the other groups. The mean values of the groups C-POST-carbon fiber post (Bisco), LIGHT-POST-translucent quartz fiber post (Bisco), D.T. LIGHT-POST-double tapered translucent quartz fiber post (Bisco), PARAPOST WHITE-glass fiber post (Coltene) and FIBREKOR--glass fiber post (Pentron) were similar and higher than the group REFORPOST-glass fiber post (Angelus).

  1. Influence of the protocol used for fibroin extraction on the mechanical properties and fiber sizes of electrospun silk mats.

    PubMed

    Aznar-Cervantes, Salvador D; Vicente-Cervantes, Daniel; Meseguer-Olmo, Luis; Cenis, José L; Lozano-Pérez, A Abel

    2013-05-01

    Silk fibroin (SF) was regenerated using three of the most common protocols described in the bibliography for the dissolution of raw SF (LiBr 9.3M, CaCl2 50 wt.% or CaCl2:EtOH:H2O 1:2:8 in molar ratio). The integrity of regenerated SF in aqueous solution was analyzed by SDS-PAGE and different profiles of degradation were observed depending on the protocol used. This fact was found to affect also the aqueous solubility of the freeze dried protein. These different SFs were used to produce electrospun mats using SF solutions of SF 17 wt.% in 1,1,1,1',1',1'-hexafluoro-2-propanol (HFIP) and significant differences in fiber sizes, elongation and ultimate strength values were found. This work provides a global overview of the manner that different methods of SF extraction can affect the properties of electrospun SF-mats and consequently it should be considered depending on the use they are going to be made for.

  2. Optimal source to detector separation for extracting sub-dermal chromophores in fiber optic diffuse reflectance spectroscopy: a simulation study

    NASA Astrophysics Data System (ADS)

    Sujatha, N.; Nivetha, K. Bala; Singhal, Akshay

    2014-05-01

    Localization and determination of blood region parameters in skin tissue can serve as a valuable supplement to standard non invasive techniques, especially in accessing the degree of depth of burns on skin and for the classification of vascular malformations. Quantitative optical examination of skin local blood region requires the use of depth sensitive techniques and preferential probing for assessment of data from specific layers of skin tissue. This work incorporates the depth sensitivity of diffuse reflectance spectroscopy and optimal source to detector fiber separation for maximum reflectance collection efficiency from local blood region in skin. Monte Carlo simulation for diffuse reflectance was performed on a multi layered skin tissue model consisting of epidermis, perfused dermis and localized blood region. It was found that the slope of the spatially resolved reflectance curve plotted with respect to the source to detector separation distance in semi log scale varies with the depth of the local blood region at specific wavelengths corresponding to the absorption wavelengths of hemoglobin. From the depth information obtained from the spatially resolved reflectance data, the optimum source to detector separation (SDS) is determined for maximum collection efficiency from the chromophore layer. The results obtained from simulation suggest the design of a linearly variable source to detector separation probe for preferential analysis of the depth of a specific tissue layer and subsequent determination of optimal source to detector separation for extracting the layer information.

  3. Optical fiber hybridization assay fluorosensor

    NASA Astrophysics Data System (ADS)

    Pilevar, Saeed; Davis, Christopher C.; Hodzic, Vildana; Portugal, Frank

    1999-04-01

    The present work describes an all-fiber hybridization assay sensor that relies on the evanescent field excitation of fluorescence from surface-bound fluorophores. The evanescent field is made accessible through the use of a long adiabatically tapered single-mode fiber probe. A semiconductor laser operating at 785 nm wavelength is used in a pulsed mode to excite fluorescence in the tapered region of a fiber probe using the near-infrared fluorophore IRD 41. We have carried out real-time hybridization tests for IRD 41-labeled oligonucleotide at various probe concentrations binding to complementary oligonucleotide cross-linked to the tapered fiber surface. Short oligonucleotides (20-mer) bound to the fiber surface have been used to detect near-infrared dye labeled complementary sequences at sub-nanomolar levels. Sandwich assays with total RNA were conducted to examine the capability of the biosensor for detecting bacterial cells using rRNA as the target. The results indicate that this fluorosensor is capable of detecting H. pylori in a sandwich assay at picomolar concentrations.

  4. Fluid-transport evaluation of lateral condensation, ProTaper gutta-percha and warm vertical condensation obturation techniques.

    PubMed

    Mahera, Fani; Economides, Nikolaos; Gogos, Christos; Beltes, Panagiotis

    2009-12-01

    The purpose of this study was to compare the microleakage of four obturation techniques (lateral condensation, lateral condensation of ProTaper Gutta-percha, single ProTaper Gutta-percha and warm vertical condensation) over a 3-month period. A fluid-transport model was used to measure microleakage. Sixty human-extracted teeth, divided into four groups, were prepared with ProTaper rotary instruments before the root canals were filled by one of the four examined techniques. All groups were obturated using Sultan as a root canal sealer. Microleakage was measured 7 days, 1 month and 3 months after the procedures. There were no statistically significant differences between the four groups at any of examination points (P > 0.05). The leakage was increased in all obturation techniques over the 3-month period.

  5. A fiber inclinometer using a fiber microtaper with an air-gap microcavity fiber interferometer

    NASA Astrophysics Data System (ADS)

    Feng, Zhongyao; Gang, Tingting; Hu, Manli; Qiao, Xueguang; Liu, Nan; Rong, Qiangzhou

    2016-04-01

    A micro-inclinometer is proposed and demonstrated experimentally; the device consists of a micro-fiber taper followed by an air-gap microcavity. A part of the core mode can couple to cladding modes via the taper. These cladding modes and residual core modes transmitted to downstream of the Fabry-Perot (FP) interferometer. A fraction of these modes are reflected back to the SMF by two surfaces of the FP cavity and eventually recoupled to the leading-in SMF, resulting in a well-defined interference spectrum. The fringe contrast of the interferometer is highly sensitive to fiber bending with direction-independence and thus is capable of measuring tilt angles in high resolution. In addition, the interference wavelength always remains unchanged during the fiber bending.

  6. The violin bow: taper, camber and flexibility.

    PubMed

    Gough, Colin

    2011-12-01

    An analytic, small-deflection, simplified model of the modern violin bow is introduced to describe the bending profiles and related strengths of an initially straight, uniform cross-section, stick as a function of bow hair tension. A number of illustrative bending profiles (cambers) of the bow are considered, which demonstrate the strong dependence of the flexibility of the bow on longitudinal forces across the ends of the bent stick. Such forces are shown to be comparable in strength to critical buckling loads causing excessive sideways buckling unless the stick is very straight. Non-linear, large deformation, finite element computations extend the analysis to bow hair tensions comparable with and above the critical buckling strength of the straight stick. The geometric model assumes an expression for the taper of Tourte bows introduced by Vuillaume, which is re-examined and generalized to describe violin, viola and cello bows. A comparison is made with recently published measurements of the taper and bending profiles of a particularly fine bow by Kittel.

  7. Hollow Fiber Supported Liquid Membrane Extraction Combined with HPLC-UV for Simultaneous Preconcentration and Determination of Urinary Hippuric Acid and Mandelic Acid

    PubMed Central

    Bahrami, Abdulrahman; Ghamari, Farhad; Yamini, Yadollah; Ghorbani Shahna, Farshid; Moghimbeigi, Abbas

    2017-01-01

    This work describes a new extraction method with hollow-fiber liquid-phase microextraction based on facilitated pH gradient transport for analyzing hippuric acid and mandelic acid in aqueous samples. The factors affecting the metabolites extraction were optimized as follows: the volume of sample solution was 10 mL with pH 2 containing 0.5 mol·L−1 sodium chloride, liquid membrane containing 1-octanol with 20% (w/v) tributyl phosphate as the carrier, the time of extraction was 150 min, and stirring rate was 500 rpm. The organic phase immobilized in the pores of a hollow fiber was back-extracted into 24 µL of a solution containing sodium carbonate with pH 11, which was placed inside the lumen of the fiber. Under optimized conditions, the high enrichment factors of 172 and 195 folds, detection limit of 0.007 and 0.009 µg·mL−1 were obtained. The relative standard deviation (RSD) (%) values for intra- and inter-day precisions were calculated at 2.5%–8.2% and 4.1%–10.7%, respectively. The proposed method was successfully applied to the analysis of these metabolites in real urine samples. The results indicated that hollow-fiber liquid-phase microextraction (HF-LPME) based on facilitated pH gradient transport can be used as a sensitive and effective method for the determination of mandelic acid and hippuric acid in urine specimens. PMID:28208685

  8. Efficiency Enhancement in a Tapered Free Electron Laser by Varying the Electron Beam Radius

    SciTech Connect

    Jiao, Yi; Wu, J.; Cai, Y.; Chao, A.W.; Fawley, W.M.; Frisch, J.; Huang, Z.; Nuhn, H.-D.; Pellegrini, C.; Reiche, S.; /PSI, Villigen

    2012-02-15

    Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered after the FEL saturation. By use of ray equation approximation to combine the one-dimensional FEL theory and optical guiding approach, an explicit physical model is built to provide insight to the mechanism of the electron-radiation coherent interaction with variable undulator parameters as well as electron beam radius. The contribution of variation in electron beam radius and related transverse effects are studied based on the presented model and numerical simulation. Taking a recent studied terawatt, 120 m long tapered FEL as an example, we demonstrate that a reasonably varied, instead of a constant, electron beam radius along the undulator helps to improve the optical guiding and thus the radiation output.

  9. Optimization of extraction efficiency by shear emulsifying assisted enzymatic hydrolysis and functional properties of dietary fiber from deoiled cumin (Cuminum cyminum L.).

    PubMed

    Ma, Mengmei; Mu, Taihua; Sun, Hongnan; Zhang, Miao; Chen, Jingwang; Yan, Zhibin

    2015-07-15

    This study evaluated the optimal conditions for extracting dietary fiber (DF) from deoiled cumin by shear emulsifying assisted enzymatic hydrolysis (SEAEH) using the response surface methodology. Fat adsorption capacity (FAC), glucose adsorption capacity (GAC), and bile acid retardation index (BRI) were measured to evaluate the functional properties of the extracted DF. The results revealed that the optimal extraction conditions included an enzyme to substrate ratio of 4.5%, a reaction temperature of 57 °C, a pH value of 7.7, and a reaction time of 155 min. Under these conditions, DF extraction efficiency and total dietary fiber content were 95.12% and 84.18%, respectively. The major components of deoiled cumin DF were hemicellulose (37.25%) and cellulose (33.40%). FAC and GAC increased with decreasing DF particle size (51-100 μm), but decreased with DF particle sizes <26 μm; BRI increased with decreasing DF particle size. The results revealed that SEAEH is an effective method for extracting DF. DF with particle size 26-51 μm had improved functional properties.

  10. Optical fiber loops and helices: tools for integrated photonic device characterization and microfluidic trapping

    NASA Astrophysics Data System (ADS)

    Ren, Yundong; Zhang, Rui; Ti, Chaoyang; Liu, Yuxiang

    2016-09-01

    Tapered optical fibers can deliver guided light into and carry light out of micro/nanoscale systems with low loss and high spatial resolution, which makes them ideal tools in integrated photonics and microfluidics. Special geometries of tapered fibers are desired for probing monolithic devices in plane as well as optical manipulation of micro particles in fluids. However, for many specially shaped tapered fibers, it remains a challenge to fabricate them in a straightforward, controllable, and repeatable way. In this work, we fabricated and characterized two special geometries of tapered optical fibers, namely fiber loops and helices, that could be switched between one and the other. The fiber loops in this work are distinct from previous ones in terms of their superior mechanical stability and high optical quality factors in air, thanks to a post-annealing process. We experimentally measured an intrinsic optical quality factor of 32,500 and a finesse of 137 from a fiber loop. A fiber helix was used to characterize a monolithic cavity optomechanical device. Moreover, a microfluidic "roller coaster" was demonstrated, where microscale particles in water were optically trapped and transported by a fiber helix. Tapered fiber loops and helices can find various applications ranging from on-the-fly characterization of integrated photonic devices to particle manipulation and sorting in microfluidics.

  11. Electromagnetic field tapering using all-dielectric gradient index materials

    PubMed Central

    Yi, Jianjia; Piau, Gérard-Pascal; de Lustrac, André; Burokur, Shah Nawaz

    2016-01-01

    The concept of transformation optics (TO) is applied to control the flow of electromagnetic fields between two sections of different dimensions through a tapering device. The broadband performance of the field taper is numerically and experimentally validated. The taper device presents a graded permittivity profile and is fabricated through three-dimensional (3D) polyjet printing technology using low-cost all-dielectric materials. Calculated and measured near-field mappings are presented in order to validate the proposed taper. A good qualitative agreement is obtained between full-wave simulations and experimental tests. Such all-dielectric taper paves the way to novel types of microwave devices that can be easily fabricated through low-cost additive manufacturing processes. PMID:27464989

  12. Electromagnetic field tapering using all-dielectric gradient index materials

    NASA Astrophysics Data System (ADS)

    Yi, Jianjia; Piau, Gérard-Pascal; de Lustrac, André; Burokur, Shah Nawaz

    2016-07-01

    The concept of transformation optics (TO) is applied to control the flow of electromagnetic fields between two sections of different dimensions through a tapering device. The broadband performance of the field taper is numerically and experimentally validated. The taper device presents a graded permittivity profile and is fabricated through three-dimensional (3D) polyjet printing technology using low-cost all-dielectric materials. Calculated and measured near-field mappings are presented in order to validate the proposed taper. A good qualitative agreement is obtained between full-wave simulations and experimental tests. Such all-dielectric taper paves the way to novel types of microwave devices that can be easily fabricated through low-cost additive manufacturing processes.

  13. Electromagnetic field tapering using all-dielectric gradient index materials.

    PubMed

    Yi, Jianjia; Piau, Gérard-Pascal; de Lustrac, André; Burokur, Shah Nawaz

    2016-07-28

    The concept of transformation optics (TO) is applied to control the flow of electromagnetic fields between two sections of different dimensions through a tapering device. The broadband performance of the field taper is numerically and experimentally validated. The taper device presents a graded permittivity profile and is fabricated through three-dimensional (3D) polyjet printing technology using low-cost all-dielectric materials. Calculated and measured near-field mappings are presented in order to validate the proposed taper. A good qualitative agreement is obtained between full-wave simulations and experimental tests. Such all-dielectric taper paves the way to novel types of microwave devices that can be easily fabricated through low-cost additive manufacturing processes.

  14. Functional significance of the taper of vertebrate cone photoreceptors

    PubMed Central

    Hárosi, Ferenc I.

    2012-01-01

    Vertebrate photoreceptors are commonly distinguished based on the shape of their outer segments: those of cones taper, whereas the ones from rods do not. The functional advantages of cone taper, a common occurrence in vertebrate retinas, remain elusive. In this study, we investigate this topic using theoretical analyses aimed at revealing structure–function relationships in photoreceptors. Geometrical optics combined with spectrophotometric and morphological data are used to support the analyses and to test predictions. Three functions are considered for correlations between taper and functionality. The first function proposes that outer segment taper serves to compensate for self-screening of the visual pigment contained within. The second function links outer segment taper to compensation for a signal-to-noise ratio decline along the longitudinal dimension. Both functions are supported by the data: real cones taper more than required for these compensatory roles. The third function relates outer segment taper to the optical properties of the inner compartment whereby the primary determinant is the inner segment’s ability to concentrate light via its ellipsoid. In support of this idea, the rod/cone ratios of primarily diurnal animals are predicted based on a principle of equal light flux gathering between photoreceptors. In addition, ellipsoid concentration factor, a measure of ellipsoid ability to concentrate light onto the outer segment, correlates positively with outer segment taper expressed as a ratio of characteristic lengths, where critical taper is the yardstick. Depending on a light-funneling property and the presence of focusing organelles such as oil droplets, cone outer segments can be reduced in size to various degrees. We conclude that outer segment taper is but one component of a miniaturization process that reduces metabolic costs while improving signal detection. Compromise solutions in the various retinas and retinal regions occur between

  15. Comparative study of the variability of 0.06 tapered rotary endodontic files to current taper standards.

    PubMed

    Hatch, Garth W; Roberts, Steven; Joyce, Anthony P; Runner, Royce; McPherson, James C

    2008-04-01

    This study compared the taper variation among Profile, Guidance, and EndoSequence 0.06 tapered rotary files to current standards. Fifteen files of sizes 35, 40, and 45 from each manufacturer were evaluated for a total of 135 files. A digital image of the first 4 mm of each file was captured with light microscope at 22x, calibrated for 0.001-mm accuracy, and analyzed. The diameter of each file was measured at 1 and 4 mm, and the taper was calculated. Of the 3 file systems, 100% of the Profile files, 97.8% of the Guidance files, and 86.7% of the EndoSequence files fell within +/-0.02 taper. All file systems demonstrated variability within their groups. A series of chi(2) analyses indicated that manufacturers tend to produce Guidance and Profile tapers slightly under the ideal 0.06 taper (P < .05). The tapers of EndoSequence files were just as likely to be over or under the advertised 0.06 taper (P > .05).

  16. Matched cascade of bandgap-shift and frequency-conversion using stimulated Raman scattering in a tapered hollow-core photonic crystal fibre.

    PubMed

    Beaudou, B; Couny, F; Wang, Y Y; Light, P S; Wheeler, N V; Gérôme, F; Benabid, F

    2010-06-07

    We report on a novel means which lifts the restriction of the limited optical bandwidth of photonic bandgap hollow-core photonic crystal fiber on generating high order stimulated Raman scattering in gaseous media. This is based on H(2)-filled tapered HC-PCF in which the taper slope is matched with the effective length of Raman process. Raman orders outside the input-bandwidth of the HC-PCF are observed with more than 80% quantum-conversion using a compact, low-power 1064 nm microchip laser. The technique opens prospects for efficient sources in spectral regions that are poorly covered by currently existing lasers such as mid-IR.

  17. Gold Coating of Fiber Tips in Near-Field Scanning Optical Microscopy

    NASA Technical Reports Server (NTRS)

    Vikram, Chandra S.; Witherow, William K.

    2000-01-01

    We report what is believed to be the first experimental demonstration of gold coating by a chemical baking process on tapered fiber tips used in near-field scanning optical microscopy. Many tips can be simultaneously coated.

  18. Design of Structurally Efficient Tapered Struts (SETS)

    NASA Technical Reports Server (NTRS)

    Deo, Ravi; Benner, Harry; Vincent, Dawson; Olason, Eric; Harrison, Richard

    2010-01-01

    A study was conducted to develop mass efficient composite struts. A closed-form design methodology for composite struts was developed using well established analyses to predict Euler buckling, local wall buckling; compression strength, damage tolerance, and interlaminar shear at geometric gradients. The methodology was coded in a spreadsheet suitable for convenient and rapid sizing of tapered composite struts. This spreadsheet analysis was used to determine the influence of several variables such as material stiffness, strut diameter, and material allowables on strut weight for given loading conditions. The comparison showed that, while the Park Aerospace design method was well suited to preliminary sizing for a conservative design, the closed-form-analyses-based spreadsheet accounts for all possible failure modes and is a good optimum strut design tool. The report concludes with a set of recommendations for future work in analytical design and analysis methodology enhancements.

  19. Hierarchical tapered bar elements undergoing axial deformation

    NASA Technical Reports Server (NTRS)

    Ganesan, N.; Thampi, S. K.

    1992-01-01

    A method is described to model the dynamics of tapered axial bars of various cross sections based on the well-known Craig/Bampton component mode synthesis technique. This element is formed in terms of the static constraint modes and interface restrained normal modes. This is in contrast with the finite elements as implemented in NASTRAN where the interface restrained normal modes are neglected. These normal modes are in terms of Bessel functions. Restoration of a few of these modes leads to higher accuracy with fewer generalized coordinates. The proposed models are hierarchical so that all lower order element matrices are embedded in higher order element matrices. The advantages of this formulation compared to standard NASTRAN truss element formulation are demonstrated through simple numerical examples.

  20. Optical fiber sensors for measurement strain and vibration

    NASA Astrophysics Data System (ADS)

    Mikel, Bretislav; Helan, Radek; Buchta, Zdenek; Holík, Milan; Jelinek, Michal; Cip, Ondrej

    2015-01-01

    We present optical fiber sensors to measurement strain and vibration. The sensors are based on fiber Bragg gratings (FBG). We prepared construction of strain sensors with respect to its implementation on the outer surface of concrete structures and with compensation of potential temperature drifts. These sensors are projected with look forward to maximal elongation and strength which can be applied to the sensor. Each sensor contains two optical fibers with FBGs. One FBG is glued into the sensor in points of fixation which are in the line with mounting holes. This FBG is prestressed to half of measurement range, than the stretching and pressing can be measured simultaneously by one FBG. The second FBG is placed inside the sensor without fixation to measure temperature drifts. The sensor can be used to structure health monitoring. The sensors to measurement vibration are based on tilted fiber Bragg grating (TFBG) with fiber taper. The sensor uses the TFBG as a cladding modes reflector and fiber taper as a bend-sensitive recoupling member. The lower cladding modes (ghost), reflected from TFBG, is recoupled back into the fiber core via tapered fiber section. We focused on optimization of TFBG tilt angle to reach maximum reflection of the ghost and taper parameters. In this article we present complete set-up, optical and mechanical parameters of both types of sensors.

  1. Synthesis of silver nanoparticles using aqueous extracts of Heterotheca inuloides as reducing agent and natural fibers as templates: Agave lechuguilla and silk.

    PubMed

    Morales-Luckie, Raúl A; Lopezfuentes-Ruiz, Aldo Adrián; Olea-Mejía, Oscar F; Liliana, Argueta-Figueroa; Sanchez-Mendieta, Víctor; Brostow, Witold; Hinestroza, Juan P

    2016-12-01

    Silver nanoparticles (Ag NPs) were synthesized using a one-pot green methodology with aqueous extract of Heterotheca inuloides as a reducing agent, and the support of natural fibers: Agave lechuguilla and silk. UV-Vis spectroscopy, X-Ray photoelectron spectroscopy XPS and transmission electron microscopy TEM were used to characterize the resulting bionanocomposite fibers. The average size of the Ag NPs was 16nm and they exhibited low polydispersity. XPS studies revealed the presence of only metallic Ag in the nanoparticles embedded in Agave. lechuguilla fibers. Significant antibacterial activities against gram-negative Escherichia coli and gram-positive Staphylococcus aureus were determined. AgO as well as metallic Ag phases were detected when silk threads were used as a substrates hinting at the active role of substrate during the nucleation and growth of Ag NPs. These bionanocomposites have excellent mechanical properties in tension which in addition to the antibacterial properties indicate the potential use of these modified natural fibers in surgical and biomedical applications.

  2. Mode Transition of RNA Trap by Electric and Hydraulic Force Field in Microfluidic Taper Shape Channel

    NASA Astrophysics Data System (ADS)

    Takamura, Yuzuru; Ueno, Kunimitsu; Nagasaka, Wako; Tomizawa, Yuichi; Tamiya, Eiichi

    2007-03-01

    We have discovered a phenomenon of accumulation of DNA near the constricted position of a microfluidic chip with taper shaped channel when both hydro pressure and electric field are applied in opposite directions. However, RNA has not been able to trap so far, unlike huge and uniformly double stranded DNA molecules, RNAs are smaller in size and single stranded with complicated conformation like blocks in lysed cell solution. In this paper, we will report not only large but also small RNA (100˜10b) are successfully trapped in relatively large microfluidic taper shape channel (width >10um). RNA are trapped in circular motion near the constricted position of taper shape channel, and the position and shape of the trapped RNA are controlled and make mode transition by changing the hydraulic and the electric force. Using this technique, smaller size molecule can be trapped in larger micro fluidic structure compared to the trap using dielectrophoresis. This technique is expected to establish easy and practical device as a direct total RNA extraction tool from living cells or tissues.

  3. Development of small bore, high speed tapered roller bearing

    NASA Technical Reports Server (NTRS)

    Morrison, F. R.; Gassel, S. S.; Bovenkerk, R. L.

    1981-01-01

    The performance of four rolling bearing configurations for use on the input pinion shaft of a proposed commercial helicopter transmission was evaluated. The performance characteristics of a high speed tapered roller bearing operating under conditions comparable to those existing at this input pinion shaft were defined. The tapered roller bearing shaft support configuration was developed for the gearbox using commercially available bearing designings. The configuration was optimized and interactive thermomechanically system analyzed. Automotive pinion quality tapered roller bearings were found to be reliable under load and speed conditions in excess of those anticipated in the helicopter transmission. However, it is indicated that the elastohydrodynamic lubricant films are inadequate.

  4. Free torsional vibrations of tapered cantilever I-beams

    NASA Astrophysics Data System (ADS)

    Rao, C. Kameswara; Mirza, S.

    1988-08-01

    Torsional vibration characteristics of linearly tapered cantilever I-beams have been studied by using the Galerkin finite element method. A third degree polynomial is assumed for the angle of twist. The analysis presented is valid for long beams and includes the effect of warping. The individual as well as combined effects of linear tapers in the width of the flanges and the depth of the web on the torsional vibration of cantilever I-beams are investigated. Numerical results generated for various values of taper ratios are presented in graphical form.

  5. Some novel features of an FEL oscillator with tapered undulator

    SciTech Connect

    Saldin, E.L.; Schneidmiller, E.A.; Yurkov, M.V.

    1995-12-31

    A one-dimensional analysis of an FEL oscillator with a linear undulator tapering is presented. Some principally novel results have been obtained. The origin of these results is in principal difference between the FEL oscillator and an FEL amplifier. In the case of the FEL amplifier the frequency of the amplified wave and all the other parameters are defined by an experimenter. Contrary to this, the case of the FEL oscillator with tapered undulator is more complicated. The lasing frequency is defined by the maximum of the small-signal gain and depends on the tapering depth in some complex way.

  6. Phase-locked loop based on machine surface topography measurement using lensed fibers.

    PubMed

    Kang, Jin-Ho; Lee, ChaBum; Joo, Jae-Young; Lee, Sun-Kyu

    2011-02-01

    We present the phase-locked loop (PLL)-based metrology concept using lensed fibers for on-machine surface topography measurement. The shape of a single-mode fiber at the endface was designed using an ABCD matrix method, and two designed lensed fibers-the ball type and the tapered type-were fabricated, and the performance was evaluated, respectively. As a result, the interferometric fringe was not found in the case of the ball lensed fiber, but the machined surface could be measured by utilization of autofocusing and intensity methods. On the other hand, a very clear Fizeau interferometric fringe was observed in the case of the tapered lensed fiber. Its performance was compared with the results of the capacitance sensor and a commercially available white-light interferometer. We confirmed that PLL-based surface profile measurement using the tapered and ball lensed fibers can be applied for on-machine surface topography measurement applications.

  7. Phase-locked loop based on machine surface topography measurement using lensed fibers

    SciTech Connect

    Kang, Jin-Ho; Lee, ChaBum; Joo, Jae-Young; Lee, Sun-Kyu

    2011-02-01

    We present the phase-locked loop (PLL)-based metrology concept using lensed fibers for on-machine surface topography measurement. The shape of a single-mode fiber at the endface was designed using an ABCD matrix method, and two designed lensed fibers--the ball type and the tapered type--were fabricated, and the performance was evaluated, respectively. As a result, the interferometric fringe was not found in the case of the ball lensed fiber, but the machined surface could be measured by utilization of autofocusing and intensity methods. On the other hand, a very clear Fizeau interferometric fringe was observed in the case of the tapered lensed fiber. Its performance was compared with the results of the capacitance sensor and a commercially available white-light interferometer. We confirmed that PLL-based surface profile measurement using the tapered and ball lensed fibers can be applied for on-machine surface topography measurement applications.

  8. Poly-3-hydroxy butyric acid interaction with the transgenic flax fibers: FT-IR and Raman spectra of the composite extracted from a GM flax

    NASA Astrophysics Data System (ADS)

    Wróbel-Kwiatkowska, Magdalena; Żuk, Magdalena; Szopa, Jan; Dymińska, Lucyna; Mączka, Mirosław; Hanuza, Jerzy

    2009-07-01

    The FT-IR and FT-Raman studies have been performed on commercial 3-hydroxy-butyric acid, commercial poly-3-hydroxy butyric acid as well as poly-3-hydroxy butyric acid (PHB) produced by bacteria. The data were compared to those obtained for poly-3-hydroxy butyric acid extracted from natural and genetically modified flax. Genetically modified flax was generated by expression of three bacterial genes coding for synthesis of poly-3-hydroxy butyric acid. Thus transgenic flaxes were enhanced with different amount of the PHB. The discussion of polymer structure and vibrational properties has been done in order to get insight into differences among these materials. The interaction between the cellulose of flax fibers and embedded poly-3-hydroxybutyric acid has been also discussed. The spectroscopic data provide evidences for structural changes in cellulose and in PHB when synthesized in fibers. Based on this data it is suggesting that cellulose and PHB interact by hydrogen and ester bonds.

  9. Optimization of tapered busses for solar cell contacts

    NASA Technical Reports Server (NTRS)

    Landis, G. A.

    1979-01-01

    Some fraction of the power produced by a solar cell is necessarily lost by series resistance associated with the metallized contact grid and by shadowing of cell active area by the grid. There are several approaches to reducing these losses, such as choosing a more efficient pattern, optimizing line spacing, and using tapered buses. The present paper analyzes tapered lines and derives from this analysis a theoretical lower bound to metallization power loss, independent of pattern chosen.

  10. Fabrication and Testing of Tapered Electro-spray Nozzles

    DTIC Science & Technology

    2012-09-01

    oxidized nozzle with broken top cap. 15 The ultrasonic breaking of the etch mask was found to be a low-yield methodology, with some caps breaking...Fabrication and Testing of Tapered Electro-spray Nozzles by Brendan M. Hanrahan and C. Mike Waits ARL-TR-6226 September 2012...September 2012 Fabrication and Testing of Tapered Electro-spray Nozzles Brendan M. Hanrahan and C. Mike Waits Sensors and Electron Devices

  11. Optical inclinometer based on fibre-taper-modal Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Amaral, L. M. N.; Frazão, O.; Santos, J. L.; Lobo Ribeiro, A. B.

    2010-09-01

    An inclinometer sensor based on optical fibre-taper-modal Michelson interferometer is demonstrated. The magnitude of the tilt (bending angle of the fibre taper interferometer) is obtained by passive interferometric interrogation based on the generation of two quadrature phase-shifted signals from two fibre Bragg gratings. Optical phase-to-rotation sensitivity of 1.13 rad/degree with a 14 mrad/√Hz resolution is achieved.

  12. Multimode tapered optical light pipe for illumination systems

    NASA Astrophysics Data System (ADS)

    Romańczuk, Patryk; Pietrzycki, Marcin; Źmojda, Jacek; Kochanowicz, Marcin; Dorosz, Dominik

    2015-09-01

    In the article the multimode tapered optical light pipe for illumination systems was investigated. Based on tree light emitting diodes at the wavelength of 460 nm (blue), 528 nm (green) and 631 nm (red) possibility of white light emission on the output surface of the tapered light pipe was submitted. Influence of optical power of LEDs on the colour coordinates (CIE-1931) has been investigated.

  13. Mean Scatterer Spacing Estimation Using Multi-Taper Coherence

    PubMed Central

    Rubert, Nicholas; Varghese, Tomy

    2013-01-01

    It has been hypothesized that estimates of mean scatterer spacing are useful indicators for pathological changes to the liver. A commonly employed estimator of the mean scatterer spacing is the location of the maximum of the collapsed average of coherence of the ultrasound radio-frequency signal. To date, in ultrasound, estimators for this quantity have been calculated with a single taper. Using frequency-domain Monte Carlo simulations, we demonstrate that multi-taper estimates of coherence are superior to single-taper estimates for predicting mean scatterer spacing. Scattering distributions were modeled with Gamma-distributed scatterers for fractional standard deviations in scatterer spacings of 5, 10, and 15% at a mean scatterer spacing of 1 mm. Additionally, we demonstrate that we can distinguish between ablated liver tissue and unablated liver tissue based on signal coherence. We find that, on the average, signal coherence is elevated in the liver relative to signal coherence of received echoes from thermally ablated tissue. Additionally, our analysis indicates that a tissue classifier utilizing the multi-taper estimate of coherence has the potential to distinguish between ablated and unablated tissue types better than a single-taper estimate of coherence. For a gate length of 5 mm, we achieved an error rate of only 8.7% when sorting 23 ablated and 23 unablated regions of interest (ROIs) into classes based on multi-taper calculations of coherence. PMID:25004470

  14. Molecular Dynamics Simulations of Penetrants in Microphase Separated Tapered Diblock Copolymers

    NASA Astrophysics Data System (ADS)

    Seo, Youngmi; Brown, Jonathan R.; Hall, Lisa M.

    Tapered AB diblock copolymers contain pure A and B monomer blocks on the ends with a tapered midblock of intermediate composition, providing taper length as an additional tuning parameter to control microphase separation and interfacial behavior. We model the midblock as a statistical linear gradient from pure A to pure B. Recent experiments with salt dissolved in one of microphases show that a certain length of taper increases ion conductivity while the same length of inverse taper lowers conductivity. We perform coarse-grained molecular dynamics simulations of tapered copolymers with monomer sized penetrants, which have preferential interactions with one microphase, to better understand this observation and the general effects of tapering on dynamics. We calculate penetrant diffusion, polymer relaxation times, and other quantities over the range from 0% (diblock) to 100% (full gradient) taper length, with the taper direction either normal or inverse (with the A side of the taper connected to the pure B block). Normal taper results typically lie between those of diblocks and full gradients, while inverse tapers show strong nonmonotonic behavior as a function of taper length. For intermediate length inverse tapers, penetrant and monomer dynamics are significantly slower than those of diblocks or normal tapers, and this relates to the folding of the inverse chains back and forth across the interface. To provide further insight, we also compare to the dynamics of random copolymers of various compositions. Based upon work supported by NSF Grant 1454343.

  15. Preparation of molecularly imprinted solid-phase microextraction fiber for the selective removal and extraction of the antiviral drug abacavir in environmental and biological matrices.

    PubMed

    Terzopoulou, Zoi; Papageorgiou, Myrsini; Kyzas, George Z; Bikiaris, Dimitrios N; Lambropoulou, Dimitra A

    2016-03-24

    In the present study, a molecularly imprinted solid-phase microextraction fiber (MIP-SPMEf) was synthesized and applied for the selective removal and extraction of the antiviral drug, abacavir (ABA). Morphology and structure characterization of fibers were performed by scanning electron microscopy and Fourier transform infrared spectra, respectively. The effects on the adsorption behavior of the process parameters were studied and the equilibrium data were fitted by the Langmuir, Freundlich and Langmuir-Freundlich models. The maximum adsorption capability (Qmax) was determined by Langmuir- Freundlich model and was 149 mg/g for MIP-SPMEf. In the next step, SPME methodology followed by liquid desorption and liquid chromatography with mass spectrometry (LC/MS) has been developed and evaluated for the determination of the target compound in environmental and biological matrices (surface waters, wastewaters and urine). Parameters that could influence SPME efficiency were investigated. Then, optimization of stirring speed, extraction time and salt content was carried out by using a central composite design (CCD) and response surface methodology (RSM). A quadratic model between dependent and independent variables was built. Under the optimum conditions (extraction time 40 min, stirring rate 650 rpm and salt content 0.3% NaCl w/v) the validated method presented a high sensitivity and selectivity with LODs and LOQs in the range of 10.1-13.6 and 33.3-43.9 ng/L, respectively. The developed method was successfully applied to the analysis of ABA in real samples. The percentage extraction efficiency ranged from 88 to 99% revealing good accuracy and absence of matrix effects.

  16. Single mode variable-sensitivity fiber optic sensors

    NASA Technical Reports Server (NTRS)

    Murphy, K. A.; Fogg, B. R.; Gunther, M. F.; Claus, R. O.

    1992-01-01

    We review spatially-weighted optical fiber sensors that filter specific vibration modes from one dimensional beams placed in clamped-free and clamped-clamped configurations. The sensitivity of the sensor is varied along the length of the fiber by tapering circular-core, dual-mode optical fibers. Selective vibration mode suppression on the order of 10 dB was obtained. We describe experimental results and propose future extensions to single mode sensor applications.

  17. Comparisons of minicard ratings to ion chromatography sugar profiles in cotton fiber water extract and minicard sticky spot material

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Specific levels and ratios of the carbohydrates melezitose and trehalulose deposited on the surface of cotton fibers are indicators of whitefly or aphid contamination. These deposits could cause stickiness problems during cotton ginning and textile processing. The concept of cotton stickiness is hi...

  18. Wavelength-codified fiber laser hydrogen detector

    NASA Astrophysics Data System (ADS)

    Ortigosa-Blanch, A.; Díez, A.; González-Segura, A.; Cruz, J. L.; Andrés, M. V.

    2005-11-01

    We report a scheme for an optical hydrogen detector that codifies the information in wavelength. The system is based on an erbium-doped fiber laser with two coupled cavities and a Palladium-coated tapered fiber within one of the laser cavities. The tapered fiber acts as the hydrogen-sensing element. When the sensing element is exposed to a hydrogen atmosphere, its attenuation decreases changing the cavity losses. This change leads the system to switch lasing from the wavelength of the auxiliary cavity to the characteristic wavelength of the cavity which contains the sensing element. The detection level can be shifted by adjusting the reflective elements of the cavity containing the sensing element.

  19. A review of Thulium fiber laser ablation of kidney stones

    NASA Astrophysics Data System (ADS)

    Fried, Nathaniel M.; Blackmon, Richard L.; Irby, Pierce B.

    2011-02-01

    The clinical solid-state Holmium:YAG laser lithotripter (λ=2120 nm) is capable of operating at high pulse energies, but its efficient operation is limited to low pulse rates during lithotripsy. The diode-pumped experimental Thulium Fiber Laser (λ=1908 nm) is limited to low pulse energies, but can operate at high pulse rates. This review compares stone ablation threshold, ablation rate, and retropulsion effects for Ho:YAG and TFL. Laser lithotripsy complications also include optical fiber bending failure resulting in endoscope damage and low irrigation rates leading to poor visibility. Both problems are related to fiber diameter and limited by Ho:YAG laser multimode spatial beam profile. This study exploits TFL spatial beam profile for higher power transmission through smaller fibers. A short taper is also studied for expanding TFL beam at the distal tip of a small-core fiber. Stone mass loss, stone crater depths, fiber transmission losses, fiber burn-back, irrigation rates, and deflection through a flexible ureteroscope were measured for tapered fiber and compared with conventional fibers. The stone ablation threshold for TFL was four times lower than for Ho:YAG. Stone retropulsion with Ho:YAG increased linearly with pulse energy. Retropulsion with TFL was minimal at pulse rates < 150 Hz, then rapidly increased at higher pulse rates. TFL beam profile provides higher laser power through smaller fibers than Ho:YAG laser, potentially reducing fiber failure and endoscope damage and allowing greater irrigation rates for improved visibility and safety. Use of a short tapered distal fiber tip also allows expansion of the laser beam, resulting in decreased fiber tip damage compared to conventional fibers, without compromising fiber bending, stone ablation efficiency, or irrigation rates.

  20. Application of carbon nanotubes modified with a Keggin polyoxometalate as a new sorbent for the hollow-fiber micro-solid-phase extraction of trace naproxen in hair samples with fluorescence spectrophotometry using factorial experimental design.

    PubMed

    Naddaf, Ezzat; Ebrahimi, Mahmoud; Es'haghi, Zarrin; Bamoharram, Fatemeh Farrash

    2015-07-01

    A sensitive technique to determinate naproxen in hair samples was developed using hollow-fiber micro-solid-phase combined with fluorescence spectrophotometry. The incorporation of multi-walled carbon nanotubes modified with a Keggin polyoxometalate into a silica matrix prepared by the sol-gel method was reported. In this research, the Keggin carbon nanotubes /silica composite was used in the pores and lumen of a hollow fiber as the hollow-fiber micro-solid-phase extraction device. The device was used for the microextraction of the analyte from hair and water samples under the optimized conditions. An orthogonal array experimental design with an OA24 (4(6) ) matrix was employed to optimize the conditions. The effect of six factors influencing the extraction efficiency was investigated: pH, salt, volume of donor and desorption phase, extraction and desorption time. The effect of each factor was estimated using individual contributions as response functions in the screening process. Analysis of variance was employed for estimating the main significant factors and their contributions in the extraction. Calibration curve plot displayed linearity over a range of 0.2-10 ng/mL with detection limits of 0.072 and 0.08 ng/mL for hair and aqueous samples, respectively. The relative recoveries in the hair and aqueous matrices ranged from 103-95%. The relative standard deviation for fiber-to-fiber repeatability was 3.9%.

  1. Tapered Implants in Dentistry: Revitalizing Concepts with Technology: A Review.

    PubMed

    Wilson, T G; Miller, R J; Trushkowsky, R; Dard, M

    2016-03-01

    The most common approach to lessen treatment times is by decreasing the healing period during which osseointegration is established. Implant design parameters such as implant surface, primary stability, thread configuration, body shape, and the type of bone have to be considered to obtain this objective. The relationship that exists between these components will define the initial stability of the implant. It is believed implant sites using a tapered design and surface modification can increase the primary stability in low-density bone. Furthermore, recent experimental preclinical work has shown the possibility of attaining primary stability of immediately loaded, tapered dental implants without compromising healing and rapid bone formation while minimizing the implant stability loss at compression sites. This may be of singular importance with immediate/early functional loading of single implants placed in poor-quality bone. The selection of an implant that will provide adequate stability in bone of poor quality is important. A tapered-screw implant design will provide adequate stability because it creates pressure on cortical bone in areas of reduced bone quality. Building on the success of traditional tapered implant therapy, newer tapered implant designs should aim to maximize the clinical outcome by implementing new technologies with adapted clinical workflows.

  2. In vitro corrosion testing of modular hip tapers.

    PubMed

    Goldberg, Jay R; Gilbert, Jeremy L

    2003-02-15

    The in vivo fretting behavior of modular hip prostheses was simulated to determine the effects of material combination and a unique TiN/AlN coating on fretting and corrosion at the taper interface. Fretting current, open-circuit potential (OCP), and quantities of soluble debris were measured to determine the role of mechanically assisted crevice corrosion on fretting and corrosion of modular hip tapers. Test groups consisting of similar-alloy (Co-Cr-Mo head/Co-Cr-Mo neck), mixed-alloy (Co-Cr-Mo head/Ti-6Al-4V neck), and TiN/AlN-coated mixed-alloy modular hip taper couples were used. Loads required to initiate fretting were similar for all test groups and were well below loads produced by walking and other physical activities. Decreases in OCP and increases in fretting current observed during long-term cyclic loading were indicative of fretting and corrosion. Current measured after cessation of cyclic loading suggests that once the conditions for crevice corrosion are established, corrosion can continue in the absence of loading. The chemical, mechanical, and electrochemical measurements, along with microscopic inspections of the taper surfaces indicate that the fretting and corrosion behavior of similar- and mixed-alloy taper couples are similar and that the coated samples are more resistant to fretting and corrosion. The results of this study clearly indicate the role of mechanical loading in the corrosion process, and support the hypothesis of mechanically assisted crevice corrosion.

  3. Temperature distribution and scuffing of tapered roller bearing

    NASA Astrophysics Data System (ADS)

    Wang, Ailin; Wang, Jiugen

    2014-11-01

    In the field of aerospace, high-speed trains and automobile, etc, analysis of temperature filed and scuffing failure of tapered roller bearings are more important than ever, and the scuffing failure of elements of such rolling bearings under heavy load and high speed still cannot be effectively predicted yet. A simplified model of tapered roller bearings consisted of one inner raceway, one outer raceway and a tapered roller was established, in which the interaction of several heat sources is ignored. The contact mechanics model, temperature model and model of scuffing failure are synthesized, and the corresponding computer programs are developed to analyze the effects of bearings parameters, different material and operational conditions on thermal performance of bearings, and temperature distribution and the possibility of surface scuffing are obtained. The results show that load, speed, thermal conductivity and tapered roller materials influence temperature rise and scuffing failure of bearings. Ceramic material of tapered roller results in the decrease of scuffing possibility of bearings to a high extent than the conventional rolling bearing steel. Compared with bulk temperature, flash temperature on the surfaces of bearing elements has a little influence on maximum temperature rise of bearing elements. For the rolling bearings operated under high speed and heavy load, this paper proposes a method which can accurately calculate the possibility of scuffing failure of rolling bearings.

  4. The width-tapered double cantilever beam for interlaminar fracture testing

    NASA Technical Reports Server (NTRS)

    Bascom, W. D.; Jensen, R. M.; Bullman, G. W.; Hunston, D. L.

    1984-01-01

    The width-tapered double-cantilever-beam (WTDCB) specimen configuration used to determine the Mode-I interlaminar fracture energy (IFE) of composites has special advantages for routine development work and for quality-assurance purposes. These advantages come primarily from the simplicity of testing and the fact that the specimen is designed for constant change in compliance with crack length, so that the computation of Mode-I IFE is independent of crack length. In this paper, a simplified technique for fabrication and testing WTDCB specimens is described. Also presented are the effects of fiber orientation and specimen dimensions, a comparison of data obtained using the WTDCB specimens and other specimen geometries, and comparison of data obtained at different laboratories. It is concluded that the WTDCB gives interlaminar Mode-I IFE essentially equal to other type specimens, and that it can be used for rapid screening in resin-development work and for quality assurance of composite materials.

  5. Power-efficient production of photon pairs in a tapered chalcogenide microwire

    SciTech Connect

    Meyer-Scott, Evan Dot, Audrey; Ahmad, Raja; Li, Lizhu; Rochette, Martin; Jennewein, Thomas

    2015-02-23

    Using tapered fibers of As{sub 2}Se{sub 3} chalcogenide glass, we produce photon pairs at telecommunication wavelengths with low pump powers. We found maximum coincidences-to-accidentals ratios of 2.13 ± 0.07 for degenerate pumping with 3.2 μW average power, and 1.33 ± 0.03 for non-degenerate pumping with 1.0 μW and 1.5 μW average power of the two pumps. Our results show that the ultrahigh nonlinearity in these microwires could allow single-photon pumping to produce photon pairs, enabling the production of large entangled states, heralding of single photons after lossy transmission, and photonic quantum information processing with nonlinear optics.

  6. Optical fiber tips functionalized with semiconductor photonic crystal cavities

    NASA Astrophysics Data System (ADS)

    Shambat, Gary; Provine, J.; Rivoire, Kelley; Sarmiento, Tomas; Harris, James; Vučković, Jelena

    2011-11-01

    We demonstrate a simple and rapid epoxy-based method for transferring photonic crystal (PC) cavities to the facets of optical fibers. Passive Si cavities were measured via fiber taper coupling as well as direct transmission from the fiber facet. Active quantum dot containing GaAs cavities showed photoluminescence that was collected both in free space and back through the original fiber. Cavities maintain a high quality factor (2000-4000) in both material systems. This design architecture provides a practical mechanically stable platform for the integration of photonic crystal cavities with macroscale optics and opens the door for innovative research on fiber-coupled cavity devices.

  7. Hollow fiber-based liquid-liquid-liquid micro-extraction with osmosis: II. Application to quantification of endogenous gibberellins in rice plant.

    PubMed

    Wu, Qian; Wu, Dapeng; Duan, Chunfeng; Shen, Zheng; Guan, Yafeng

    2012-11-23

    The phenomenon and benefits of osmosis in hollow fiber-based liquid-liquid-liquid micro-extraction (HF-LLLME) were theoretically discussed in part I of this study. In this work, HF-LLLME with osmosis was coupled with high performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-triple quadrupole MS/MS) to analyze eight gibberellins (gibberellin A(1), gibberellin A(3), gibberellin A(4), gibberellin A(7), gibberellin A(8), gibberellin A(9), gibberellin A(19) and gibberellin A(20)) in rice plant samples. According to the theory of HF-LLLME with osmosis, single factor experiments, orthogonal design experiments and mass transfer simulation of extraction process were carried out to select the optimal conditions. Cyclohexanol - n-octanol (1:3, v/v) was selected as organic membrane. Donor phase of 12 mL was adjusted to pH 2 and 20% NaCl (w/v) was added. Acceptor phase with an initial volume of 20 μL was the solution of 0.12 mol L(-1) Na(2)CO(3)-NaHCO(3) buffer (pH 9). Temperature was chosen to be 30 °C and extraction time was selected to be 90 min. Under optimized conditions, this method provided good linearity (r, 0.99552-0.99991) and low limits of detection (0.0016-0.061 ng mL(-1)). Finally, this method was applied to the analysis of endogenous gibberellins from plant extract which was obtained with traditional solvent extraction of rice plant tissues, and the relative recoveries were from 62% to 166%.

  8. Head-Neck Taper Corrosion in Hip Arthroplasty

    PubMed Central

    Hussenbocus, S.; Kosuge, D.; Solomon, L. B.; Howie, D. W.; Oskouei, R. H.

    2015-01-01

    Modularity at the head-neck junction of the femoral component in THA became popular as a design feature with advantages of decreasing implant inventory and allowing adjustment of leg length, offset, and soft tissue balancing through different head options. The introduction of a new modular interface to femoral stems that were previously monoblock, or nonmodular, comes with the potential for corrosion at the taper junction through mechanically assisted crevice corrosion. The incidence of revision hip arthroplasty is on the rise and along with improved wear properties of polyethylene and ceramic, use of larger femoral head sizes is becoming increasingly popular. Taper corrosion appears to be related to all of its geometric parameters, material combinations, and femoral head size. This review article discusses the pathogenesis, risk factors, clinical assessment, and management of taper corrosion at the head-neck junction. PMID:25954757

  9. Bis(trifluoromethanesulfonyl)imide-based ionic liquids grafted on graphene oxide-coated solid-phase microextraction fiber for extraction and enrichment of polycyclic aromatic hydrocarbons in potatoes and phthalate esters in food-wrap.

    PubMed

    Hou, Xiudan; Guo, Yong; Liang, Xiaojing; Wang, Xusheng; Wang, Lei; Wang, Licheng; Liu, Xia

    2016-06-01

    A class of novel, environmental friendly ionic liquids (ILs) were synthesized by on-fiber preparation strategy and modified on graphene oxide (GO)-coated stainless steel wire, which was used as a solid-phase microextraction (SPME) fiber for efficient enrichment of polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs). Surface characteristic of the ILs and polymeric-ILs (PILs) fibers with the wave-structure were inspected by scanning electron microscope. The successfully synthesis of bis(trifluoromethanesulfonyl)imide (NTf2(-))-based ILs were also characterized by energy dispersive spectrometer analysis. Through the chromatograms of the proposed two ILs (1-aminoethyl-3-methylimidazolium bromide (C2NH2MIm(+)Br(-)), C2NH2MIm(+)NTf2(-)) and two PILs (polymeric 1-vinyl-3-hexylimidazolium bromide (poly(VHIm(+)Br(-))), poly(VHIm(+)NTf2(-)))-GO-coated fibers for the extraction of analytes, NTf2(-)-based PIL demonstrated higher extraction capacity for hydrophobic compounds than other as-prepared ILs. Analytical performances of the proposed fibers were investigated under the optimized extraction and desorption conditions coupled with gas chromatography (GC). Compared with the poly(VHIm(+)Br(-))-GO fiber, the poly(VHIm(+)NTf2(-))-GO SPME fiber brought wider linear ranges for analytes with correlation coefficient in the range of 0.9852-0.9989 and lower limits of detection ranging from 0.015-0.025μgL(-1). The obtained results indicated that the newly prepared PILs-GO coating was a feasible, selective and green microextraction medium, which could be suitable for extraction and determination of PAHs and PAEs in potatoes and food-wrap sample, respectively.

  10. Comparison between solid phase microextraction (SPME) and hollow fiber liquid phase microextraction (HFLPME) for determination of extractables from post-consumer recycled PET into food simulants.

    PubMed

    Oliveira, Éder Costa; Echegoyen, Yolanda; Cruz, Sandra Andrea; Nerin, Cristina

    2014-09-01

    Hollow fiber liquid phase microextraction (HFLPME) and solid phase microextraction (SPME) methods for pre-concentration of contaminants (toluene, benzophenone, tetracosane and chloroform) in food simulants were investigated. For HFLPME 1-heptanol, 2-octanone and dibutyl-ether were studied as extracting solvents. Analysis by gas chromatography coupled to mass spectrometry (GC-MS), flame ionization (GC-FID) and electron capture detectors (GC-ECD) were carried out. In addition, the methods were employed to evaluate the safety in use of a PET material after the recycling process (comprising washing, extrusion and solid state polymerization (SSP)) through extractability studies of the contaminants using 10% (v/v) ethanol in deionized water and 3% (w/v) acetic acid in deionized water as food simulants in different conditions: 10 days at 40°C and 2h at 70°C. The HFLPME preconcentration method provided increased sensitivity when compared to the SPME method and allowed to analyze concentration levels below 10 µg surrogate per kg food simulant. The results of the extractability studies showed considerable reductions after the extrusion and SSP processes and indicated the compliance with regulations for using recycled PET in contact with food.

  11. Wind-tunnel research comparing lateral control devices, particularly at high angles of attack IX : tapered wings with ordinary ailerons

    NASA Technical Reports Server (NTRS)

    Weick, Fred E; Wenzinger, Carl J

    1933-01-01

    Tests were made with ordinary flap-type ailerons on two wings with different amounts of taper, one medium and the other extreme. On each wing both medium sized tapered ailerons and short wide tapered ailerons were tested.

  12. Technology Development for Tapered-Wiggler Free-Electron Lasers

    DTIC Science & Technology

    1984-04-01

    canting can produce equal e-beam focusing in each of the two - transverse directions. Thus the e-beam focusing characteristics of a helical wiggler can...Both taper prescriptions require a modest frequency chirp of less than 1.5 percent during start-up. 3.2 VARIALE -TAPER WIGGLER EMAWQEM DEVEPHE T This...with Nonuniform Wigglers," IEEE J. Quantum Electron. QE-16, 335 (1980). 4-8. J.P. Blewett and R. Chasman, "Orbits and Fields in the Helical Wiggler," J

  13. Impedance Scaling for Small-angle Tapers and Collimators

    SciTech Connect

    Stupakov, G.; /SLAC

    2010-02-11

    In this note I will prove that the impedance calculated for a small-angle collimator or taper, of arbitrary 3D profile, has a scaling property that can greatly simplify numerical calculations. This proof is based on the parabolic equation approach to solving Maxwell's equation developed in Refs. [1, 2]. We start from the parabolic equation formulated in [3]. As discussed in [1], in general case this equation is valid for frequencies {omega} >> c/a where a is a characteristic dimension of the obstacle. However, for small-angle tapers and collimators, the region of validity of this equation extends toward smaller frequencies and includes {omega} {approx} c/a.

  14. Opioid abstinence reinforcement delays heroin lapse during buprenorphine dose tapering.

    PubMed

    Greenwald, Mark K

    2008-01-01

    A positive reinforcement contingency increased opioid abstinence during outpatient dose tapering (4, 2, then 0 mg/day during Weeks 1 through 3) in non-treatment-seeking heroin-dependent volunteers who had been maintained on buprenorphine (8 mg/day) during an inpatient research protocol. The control group (n=12) received $4.00 for completing assessments at each thrice-weekly visit during dose tapering; 10 of 12 lapsed to heroin use 1 day after discharge. The abstinence reinforcement group (n=10) received $30.00 for each consecutive opioid-free urine sample; this significantly delayed heroin lapse (median, 15 days).

  15. Effects of extraction methods and particle size distribution on the structural, physicochemical, and functional properties of dietary fiber from deoiled cumin.

    PubMed

    Ma, Meng-Mei; Mu, Tai-Hua

    2016-03-01

    This study evaluated the effects of alkali extraction, enzymatic hydrolysis, shear emulsifying assisted enzymatic hydrolysis, and particle size distribution on the chemical composition and the structural, physicochemical, and functional properties of deoiled cumin dietary fibers (AEDF, EHDF and SEDF). Compared to AEDF and EHDF, SEDF had the highest total dietary fiber, crystalline regions, water swelling capacity (6.79-7.98ml/g), oil adsorption capacity (6.12-7.25%), α-amylase activity inhibition ratio (14.79-21.84%), glucose adsorption capacity (2.02-60.86%), and bile acid retardation index (16.34-50.08%). DFs sieved with mesh sizes >80 exhibited better physicochemical and functional properties than unsieved DFs. The physicochemical properties of sieved DFs improved with increasing sieve mesh sizes (40-120), but decreased with sieve mesh sizes >120, while the functional properties increased with increasing sieve mesh sizes. SEDF sieved with mesh sizes 100-150 can be used as functional ingredients due to its excellent physicochemical and functional properties.

  16. Tapered plasma channels to phase-lock accelerating and focusing forces in laser-plasma accelerators

    SciTech Connect

    Rittershofer, W.; Schroeder, C.B.; Esarey, E.; Gruner, F.J.; Leemans, W.P.

    2010-05-17

    Tapered plasma channels are considered for controlling dephasing of a beam with respect to a plasma wave driven by a weakly-relativistic, short-pulse laser. Tapering allows for enhanced energy gain in a single laser plasma accelerator stage. Expressions are derived for the taper, or longitudinal plasma density variation, required to maintain a beam at a constant phase in the longitudinal and/or transverse fields of the plasma wave. In a plasma channel, the phase velocities of the longitudinal and transverse fields differ, and, hence, the required tapering differs. The length over which the tapered plasma density becomes singular is calculated. Linear plasma tapering as well as discontinuous plasma tapering, which moves beams to adjacent plasma wave buckets, are also considered. The energy gain of an accelerated electron in a tapered laser-plasma accelerator is calculated and the laser pulse length to optimize the energy gain is determined.

  17. Effects of taper on drilling and cutting with a pulsed laser

    NASA Astrophysics Data System (ADS)

    Angell, James; Ho, Wen; Schaeffer, Ronald D.

    1997-04-01

    An inherent characteristic of laser machined features is taper. For a particular laser the degree of taper is largely dependent on two things: the type of material being machined and the laser energy per unit area or fluence at the processing surface. The latter of these is dependent on different parameters for the three lasers mentioned above. In this paper we review the particular laser parameters that control taper and what degree of taper can be expected for certain materials. More often than not taper is a nondesirable characteristic and is, in many cases, the limiting factor regarding the maximum thickness of material that a laser is practically capable of drilling or cutting through. We therefore discuss methods of minimizing taper and its effects. Under some circumstances taper can be used to one's advantage to achieve a desired feature size if one has control over the taper angle.

  18. Effects of taper on drilling and cutting with a pulsed laser

    NASA Astrophysics Data System (ADS)

    Angell, James; Ho, Wen; Schaeffer, Ronald D.

    1997-03-01

    An inherent characteristic of laser machined features is taper. For a particular laser the degree of taper is largely dependent on two things: the type of material being machined and the laser energy per unit area or fluence at the processing surface. The latter of these is dependent on different parameters for the three lasers mentioned above. In this paper we review the particular laser parameters that control taper and what degree of taper can be expected for certain materials. More often than not taper is a nondesirable characteristic and is, in many cases, the limiting factor regarding the maximum thickness of material that a laser is practically capable of drilling or cutting through. We therefore discuss methods of minimizing taper and its effects. Under some circumstances taper can be used to one's advantage to achieve a desired feature size if one has control over the taper angle.

  19. Experimental Investigation of Superradiance in a Tapered Free-Electron Laser Amplifier

    SciTech Connect

    Hidaka, Y.; She, Y.; Murphy, J.B.; Podobedov, B.; Seletskiy, S.; Yang, X.

    2011-03-28

    We report experimental studies of the effect of undulator tapering on superradiance in a single-pass high-gain free-electron laser (FEL) amplifier. The experiments were performed at the Source Development Laboratory (SDL) of National Synchrotron Light Source (NSLS). Efficiency was nearly tripled with tapering. Both the temporal and spectral properties of the superradiant FEL along the uniform and tapered undulator were experimentally characterized using frequency-resolved optical gating (FROG) images. Numerical studies predicted pulse broadening and spectral cleaning by undulator tapering Pulse broadening was experimentally verified. However, spectral cleanliness degraded with tapering. We have performed first experiments with a tapered undulator and a short seed laser pulse. Pulse broadening with tapering expected from simulations was experimentally confirmed. However, the experimentally obtained spectra degraded with tapering, whereas the simulations predicted improvement. A further numerical study is under way to resolve this issue.

  20. Extraction of cellulose nano-crystals from old corrugated container fiber using phosphoric acid and enzymatic hydrolysis followed by sonication.

    PubMed

    Tang, Yanjun; Shen, Xiaochuang; Zhang, Junhua; Guo, Daliang; Kong, Fangong; Zhang, Nan

    2015-07-10

    Due to its amazing physicochemical properties and high environmental compatibility, cellulose nano-crystals (CNC) hold great promise for serving as a strategic platform for sustainable development. Now, there has been growing interest in the development of processes using waste or residual biomass as CNC source for addressing economic and environmental concerns. In the present work, a combined process involving phosphoric acid hydrolysis, enzymatic hydrolysis and sonication was proposed aiming to efficiently exact CNC from low-cost old corrugated container (OCC) pulp fiber. The effect of enzymatic hydrolysis on the yield and microstructure of resulting CNC was highlighted. Results showed that the enzymatic hydrolysis was effective in enhancing CNC yield after phosphoric acid hydrolysis. CNC was obtained with a yield of 23.98 wt% via the combined process with phosphoric acid concentration of 60 wt%, cellulase dosage of 2 mL (84 EGU) per 2g fiber and sonication intensity of 200 W. Moreover, the presence of enzymatic hydrolysis imparted the obtained CNC with improved dispersion, increased crystallinity and thermal stability.

  1. Conversion of Extracted Oil Cake Fibers into Bioethanol Including DDGS, Canola, Sunflower, Seasame, Soy, and Peanut for Integrated Biodiesel Processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have come up with a novel integrated approach where biodiesel processing can be potentially done in-house by producing ethanol from edible oilseeds after hexane extraction to remove residual oil. In addition, we have demonstrated how ethanol could be manufactured from widely available oil cakes ...

  2. Impedance Matching of Tapered Slot Antenna using a Dielectric Transformer

    NASA Technical Reports Server (NTRS)

    Simons, R. N.; Lee, R. Q.

    1998-01-01

    A new impedance matching technique for tapered slot antennas using a dielectric transformer is presented. The technique is demonstrated by measuring the input impedance, Voltage Standing Wave Ratio (VSWR) and the gain of a Vivaldi antenna (VA). Measured results at Ka-Band frequencies are presented and discussed.

  3. Linearly tapered slot antenna circular array for mobile communications

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Kelly, Eron; Lee, Richard Q.; Taub, Susan R.

    1993-01-01

    The design, fabrication and testing of a conformal K-band circular array is presented. The array consists of sixteen linearly tapered slot antennas (LTSA). It is fed by a 1:16 microstrip line power splitter via electromagnetic coupling. The array has an omni-directional pattern in the azimuth plane. In the elevation plane the beam is displaced above the horizon.

  4. FSW of Tapered Thickness Welds using an Adjustable Pin Tool

    NASA Technical Reports Server (NTRS)

    Adams, Glynn; Venable, Richard; Lawless, Kirby; Smelser, Jerry (Technical Monitor)

    2002-01-01

    This viewgraph presentation describes the advantages of tapered thickness welds in FSW (friction stir welding), the structure of FSW welds, the adjustable pin tool used in FSW. Other topics described include compliance and temperature measurement in a FSW system, loads and torque upon the pin tool and its ability to penetrate different metals, and the results and metallurgy of FSW welds.

  5. Tapered Roller Bearing Damage Detection Using Decision Fusion Analysis

    NASA Technical Reports Server (NTRS)

    Dempsey, Paula J.; Kreider, Gary; Fichter, Thomas

    2006-01-01

    A diagnostic tool was developed for detecting fatigue damage of tapered roller bearings. Tapered roller bearings are used in helicopter transmissions and have potential for use in high bypass advanced gas turbine aircraft engines. A diagnostic tool was developed and evaluated experimentally by collecting oil debris data from failure progression tests conducted using health monitoring hardware. Failure progression tests were performed with tapered roller bearings under simulated engine load conditions. Tests were performed on one healthy bearing and three pre-damaged bearings. During each test, data from an on-line, in-line, inductance type oil debris sensor and three accelerometers were monitored and recorded for the occurrence of bearing failure. The bearing was removed and inspected periodically for damage progression throughout testing. Using data fusion techniques, two different monitoring technologies, oil debris analysis and vibration, were integrated into a health monitoring system for detecting bearing surface fatigue pitting damage. The data fusion diagnostic tool was evaluated during bearing failure progression tests under simulated engine load conditions. This integrated system showed improved detection of fatigue damage and health assessment of the tapered roller bearings as compared to using individual health monitoring technologies.

  6. Vibration frequencies of tapered bars with nonclassical boundary conditions

    NASA Technical Reports Server (NTRS)

    Craver, W. Lionel, Jr.

    1988-01-01

    The goals for this research were revised and clarified. The goals are restated along with an evaluation of the accomplishment of the goal. All of the cases of the truncated-cone beams that were originally proposed to be solved were solved. A summary of these solutions is presented. Some cases of beams with unequal tapers were solved and are discussed.

  7. Efficiency optimization in a FEL with fields` nonadiabatic tapering

    SciTech Connect

    Goncharov, I.A.; Belyavskiy, E.D.; Silivra, A.A.

    1995-12-31

    Amplification of an electromagnetic wave in free electron lasers with a reversed guide field and right-hand polarized wiggler field is investigated both analytically and numerically. An effect of electron bunch trapping by the high frequency electromagnetic field is used for efficiency optimization. On the basis of motion stability criteria a possibility of bunches trapping by FEL parameters nonadiabatic (experimentally realizable) tapering is shown. The stability analysis of electron motion is based on Lyapunov theory for autonomy systems. A particle simulation is carried out for FEL parameters close to the experimental ones (relativistic factor {gamma}=4.75, wiggler field strength B{sub w}= 2.8 kG, guide field strength B{sub o}= -1.4 kG, operation wavelength {lambda}=6.2 mm) for the case of wiggler field tapering. Theoretically predicted rule of wiggler field tapering corresponding to FEL efficiency of 55% is approximated by stepped functions. For the experimentally realizable tapering it is found that FEL efficiency can be over 40%.

  8. Opioid Abstinence Reinforcement Delays Heroin Lapse during Buprenorphine Dose Tapering

    ERIC Educational Resources Information Center

    Greenwald, Mark K.

    2008-01-01

    A positive reinforcement contingency increased opioid abstinence during outpatient dose tapering (4, 2, then 0 mg/day during Weeks 1 through 3) in non-treatment-seeking heroin-dependent volunteers who had been maintained on buprenorphine (8 mg/day) during an inpatient research protocol. The control group (n = 12) received $4.00 for completing…

  9. Effects of Reciproc, Mtwo and ProTaper Instruments on Formation of Root Fracture

    PubMed Central

    Jalali, Sahar; Eftekhar, Behrooz; Paymanpour, Payam; Yazdizadeh, Mohammad; Jafarzadeh, Mansour

    2015-01-01

    Introduction: The aim of this study was to compare the formation of dentinal crack and craze lines in the root dentin during root canal preparation with three different NiTi endodontic systems, naming Reciproc (RCP), ProTaper Universal (PTU) and Mtwo. Methods and Materials: One hundred extracted mandibular premolars with single canals were selected and decoronated. The teeth were randomly divided into four groups of 25 each (n=25). In groups 1, 2 and 3 the teeth were prepared using Mtwo, PTU and RCP, respectively. While in group 4 (control group) the samples were left unprepared. After preparation, all specimens were sectioned perpendicular to the long axis of root at 3, 5 and 9-mm distances from the apex. The sections were then individually observed under 12× magnification using stereomicroscope. The data was analyzed using the chi-square and Fisher’s exact tests. The level of significance was set at 0.05. Results: No cracks were observed in the control group. All engine-driven systems caused dentinal cracks. Mtwo and PTU caused cracks significantly more than RCP (P<0.05). There was no significant difference between RCP and control group (P>0.05). Conclusion: All three engine-driven systems created dentinal defects. Reciproc caused less cracks than Mtwo and ProTaper Universal. PMID:26523141

  10. Simultaneous extraction and quantification of albendazole and triclabendazole using vortex-assisted hollow-fiber liquid-phase microextraction combined with high-performance liquid chromatography.

    PubMed

    Asadi, Mohammad; Haji Shabani, Ali Mohammad; Dadfarnia, Shayessteh

    2016-06-01

    A novel, simple, and rapid vortex-assisted hollow-fiber liquid-phase microextraction method was developed for the simultaneous extraction of albendazole and triclabendazole from various matrices before their determination by high-performance liquid chromatography with fluorescence detection. Several factors influencing the microextraction efficiency including sample pH, nature and volume of extraction solvent, ionic strength, vortex time, and sample volume were investigated and optimized. Under the optimal conditions, the limits of detection were 0.08 and 0.12 μg/L for albendazole and triclabendazole, respectively. The calibration curves were linear in the concentration ranges of 0.3-50.0 and 0.4-50.0 μg/L with the coefficients of determination of 0.9999 and 0.9995 for albendazole and triclabendazole, respectively. The interday and intraday relative standard deviations for albendazole and triclabendazole at three concentration levels (1.0, 10.0, and 30.0 μg/L) were in the range of 6.0-11.0 and 5.0-7.9%, respectively. The developed method was successfully applied to determine albendazole and triclabendazole in water, milk, honey, and urine samples.

  11. Loss Factor of Tapered Structures for Short Bunches

    SciTech Connect

    Blednykh, A.

    2011-03-28

    Using the electromagnetic simulation code ECHO, we have found a simple phenomenological formula that accurately describes the loss factor for short bunches traversing an axisymmetric tapered collimator. In this paper, we consider tapered collimators with rectangular cross-section and use the GdfidL code to calculate the loss factor dependence on the geometric parameters for short bunches. The results for both axisymmetric and rectangular collimators are discussed. The behaviour of the impedance of tapered structures for very short bunches in the optical regime has been determined in refs. [10,11]. Here, for the loss factors for two particular geometries, we have studied the departure from the optical regime behaviour as bunch length is increased. In both cases, the ratio of the loss factor for the tapered collimator to the loss factor in the optical regime is a function only of the scaling parameter {sigma}L/d{sup 2}. The fact that the bunch length a and the taper length L appear as a product is consistent with the recent scaling derived by Stupakov in ref. [12], since there is only a weak dependence on g. One noteworthy fact that is not a priori expected is that only the larger radius or vertical half-aperture d appears. The reduction factor is independent of b. Moreover, it is striking that the specific form involving the arctan given in Eq. (5) holds for both geometries, with only the coefficient {mu} differing by a factor of {approx}2 for flat vs round. This suggests that there may be a useful phenomenological form for more general geometries which may follow from natural extensions of Eq. (5). This possibility is presently being investigated.

  12. Fiber Laser Array

    DTIC Science & Technology

    2004-01-01

    telecommunications market and do not emphasize high powers. Because high power applications are of significant interest to the Air Force, we were interested in fiber...available from NTIC . 9. T.B. Simpson, A. Gavrielides and P. Peterson, “Extraction Characteristics of a Dual Fiber Compound Cavity,” Optics Express 10

  13. Thin Film Metal Coated Fiber Optic Hydrophone Probe

    PubMed Central

    Gopinath, R.; Arora, P.; Gandhi, G.; Daryoush, A.S.; El-Sherif, M.; Lewin, P.A.

    2010-01-01

    The purpose of this work was to improve on sensitivity performance of fiber sensor employed as Fiber Optic Hydrophone Probe (FOHP) by nano-scale thin film gold coating. The fiber is designed to provide a uniform and spatial averaging free response up to 100 MHz by etching down to an active diameter of about 9 μm. The sensitivity performance of straight cleaved (i.e. full size core and cladding) uncoated, tapered uncoated and tapered thin film gold coated fiber sensors were compared in the frequency range of 1.5 MHz to 20 MHz in the presence of acoustic pressure amplitude levels of up to 6 MPa. An unprecedented voltage sensitivity of −245 dB re 1V/uPa (560 mV/ MPa) was measured for thin film gold coated FOHP by optimizing the gold coating thickness. PMID:19881652

  14. A One-year Follow-up Study of a Tapered Hydrophilic Implant Design Using Various Placement Protocols in the Maxilla

    PubMed Central

    Zwaan, Jakob; Vanden Bogaerde, Leonardo; Sahlin, Herman; Sennerby, Lars

    2016-01-01

    Purpose: To study the clinical/radiographic outcomes and stability of a tapered implant design with a hydrophilic surface when placed in the maxilla using various protocols and followed for one year. Methods: Ninety-seven consecutive patients treated as part of daily routine in two clinics with 163 tapered implants in healed sites, in extraction sockets and together with bone augmentation procedures in the maxilla were evaluated after one year in function. Individual healing periods varying from 0 to 6 months had been used. Insertion torque (IT) and resonance frequency analysis (RFA) measurements were made at baseline. Follow-up RFA registrations were made after 6 and 12 months of loading. The marginal bone levels were measured in intraoral radiographs from baseline and after 12 months. A reference group consisting of 163 consecutive straight maxillary implants was used for the comparison of baseline IT and RFA measurements. Results: Five implants failed before loading, giving an implant survival rate of 96.9% and a prosthesis survival rate of 99.4% after one year. The mean marginal bone loss after one year was 0.5 mm (SD 0.4). The mean IT was statistically significantly higher for tapered than for straight reference implants (41.3 ± 12.0 Ncm vs 33.6 ± 12.5 Ncm, p < 0.001). The tapered implants showed a statistically insignificantly higher mean ISQ value than the straight references implants (73.7 ± 6.4 ISQ vs 72.2 ± 8.0 ISQ, p=0.119). There was no correlation between IT and marginal bone loss. There was a correlation between IT and RFA measurements (p < 0.001). Conclusion: The tapered implant showed a high survival rate and minimal marginal bone loss after one year in function when using various protocols for placement. The tapered implant showed significantly higher insertion torque values than straight reference implants. PMID:28077972

  15. Dietary fiber-rich colloids from apple pomace extraction juices do not affect food intake and blood serum lipid levels, but enhance fecal excretion of steroids in rats.

    PubMed

    Sembries, Sabine; Dongowski, Gerhard; Mehrländer, Katri; Will, Frank; Dietrich, Helmut

    2004-05-01

    The aim of this study was to investigate the effects of colloids isolated from apple pomace extraction juices (so-called B-juices) produced by enzymatic liquefaction on food intake, levels of blood serum lipids, and fecal excretion of bile acids (BA) and neutral sterols (NS) in vivo. Ten male Wistar rats per group were fed diets containing either no apple dietary fiber (DF) (control), a 5% supplementation with juice colloids, or an alcohol-insoluble substance (AIS) from apples for 6 weeks. Apple DF in diets led to lower weight gain in rats fed with B-juice colloids (P< 0.05). For these rats, food intake was not affected but was highest with feeding AIS (10% more than control) to cover energy requirements. The supplementation of diet with apple DF from extraction juices or AIS had minor effects on blood serum lipids. In rats fed either juice colloids or AIS, up to 30% (5.31 micromol/g dry weight) and 88% (7.69 micromol/g dry weight) more primary BA were excreted in feces, respectively, as compared to that in the control group (4.10 micromol/g dry weight) (P < 0.05). In cecal contents, a 15% (juice colloids) to 37% (AIS) increase in primary BA was found. In contrast, concentrations of secondary BA were lower in feces of test groups (P < 0.05). Excretion of total BA and NS was higher in rats fed apple DF (P < 0.05). Our study is the first to prove that there are beneficial physiologic effects of apple DF isolated from pomace extraction juices produced by enzymatic liquefaction. These results may help to develop such innovative juice products that are rich in DF of fruit origin for diminishing the lack of DF intake.

  16. A porous carbon derived from amino-functionalized material of Institut Lavoisier as a solid-phase microextraction fiber coating for the extraction of phthalate esters from tea.

    PubMed

    Liang, Weiqian; Wang, Juntao; Zang, Xiaohuan; Wang, Chun; Wang, Zhi

    2016-04-01

    In this work, a porous carbon derived from amino-functionalized material of Institut Lavoisier (C-NH2 -MIL-125) was prepared and coated onto a stainless-steel wire through sol-gel technique. The coated fiber was used for the solid-phase microextraction of trace levels of phthalate esters (diallyl phthalate, di-iso-butyl ortho-phthalate, di-n-butyl ortho-phthalate, benzyl-n-butyl ortho-phthalate, and bis(2-ethylhexy) ortho-phthalate) from tea beverage samples before gas chromatography with mass spectrometric analysis. Several experimental parameters that could influence the extraction efficiency such as extraction time, extraction temperature, sample pH, sample salinity, stirring rate, desorption temperature and desorption time, were investigated. Under the optimal conditions, the linearity existed in the range of 0.05-30.00 μg/L for green jasmine tea beverage samples, and 0.10-30.00 μg/L for honey jasmine tea beverage samples, with the correlation coefficients (r) ranging from 0.9939 to 0.9981. The limits of detection of the analytes for the method were 2.0-3.0 ng/L for green jasmine tea beverage sample, and 4.0-5.0 ng/L for honey jasmine tea beverage sample, depending on the compounds. The recoveries of the analytes for the spiked samples were in the range of 82.0-106.0%, and the precision, expressed as the relative standard deviations, was less than 11.1%.

  17. Efectiveness of the waveone and ProTaper D systems for removing gutta-percha with or without a solvent.

    PubMed

    Colombo, Ana Pm; Fontana, Carlos E; Godoy, Aline; De Martin, Alexandre S; Kato, Augusto S; Rocha, Daniel Gp; Pelegrine, Rina A; Bueno, Carlos Es

    2016-12-01

    Endodontic retreatment requires complete removal of the filling material and access to the apical foramen. The purpose of this study was to evaluate the effectiveness of the Wave One reciprocating system and compare it to the ProTaper D rotarysystem, with or without the use of a solvent, in removing filling material from root canals. The time required for each filling removal technique employed was also determined and compared. Forty extracted human mandibular premolars with a single, straight, flattened canal were prepared and filled. They were divided into four groups (n = 10): Group 1: ProTaper D Ni Ti rotary instruments; Group 2: ProTaper D Ni Tirotary instruments, with a solvent; Group 3: Wave One primary instrument; and Group 4: Wave One primary instrument, with a solvent. The teeth were then split along their long axis and photographed using an operating microscope with 5Xmagnification. The amount of remaining filling material was assessed with Image Tool software. The results were compared using the Kruskal Wallis test (p <0.05). There was no significant difference between groups regarding the amount of residual filling material (p > 0.05). Operative time was significantly longer in Group 3 than in groups 1, 2 and 4 (p <0.05). The Wave One system and the ProTaper D system were equally effective, with or without a solvent. The time required to remove the filling material from the canals was significantly longer in Group 3 than in the other groups.

  18. Extraction and preconcentration of tylosin from milk samples through functionalized TiO₂ nanoparticles reinforced with a hollow fiber membrane as a novel solid/liquid-phase microextraction technique.

    PubMed

    Sehati, Negar; Dalali, Nasser; Soltanpour, Shahla; Dorraji, Mir Saeed Seyed

    2014-08-01

    The aim of this study was to introduce a novel, simple, and highly sensitive preparation method for determination of tylosin in different milk samples. In the so-called functionalized TiO2 hollow fiber solid/liquid-phase microextraction method, the acceptor phase is functionalized TiO2 nanoparticles that are dispersed in the organic solvent and held in the pores and lumen of a porous polypropylene hollow fiber membrane. An effective functionalization of TiO2 nanoparticles has been done in the presence of aqueous H2 O2 and a mild acidic ambient under UV irradiation. This novel extraction method showed excellent extraction efficiency and a high enrichment factor (540.2) in comparison with conventional hollow fiber liquid-phase microextraction. All the experiments were monitored at λmax = 284 nm using a simple double beam UV-visible spectrophotometer. A Taguchi orthogonal array experimental design with an OA16 (4(5) ) matrix was employed to optimize the factors affecting the efficiency of hollow fiber solid/liquid-phase microextraction such as pH, stirring rate, salt addition, extraction time, and the volume of donor phase. This developed method was successfully applied for the separation and determination of tylosin in milk samples with a linear concentration range of 0.51-7000 μg/L (r(2) = 0.991) and 0.21 μg/L as the limit of detection.

  19. Optical fiber-based photocathode

    NASA Astrophysics Data System (ADS)

    Cǎsǎndruc, Albert; Bücker, Robert; Kassier, Günther; Miller, R. J. Dwayne

    2016-08-01

    We present the design of a back-illuminated photocathode for electron diffraction experiments based on an optical fiber, and experimental characterization of emitted electron bunches. Excitation light is guided through the fiber into the experimental vacuum chamber, eliminating typical alignment difficulties between the emitter metal and the optical trigger and position instabilities, as well as providing reliable control of the laser spot size and profile. The in-vacuum fiber end is polished and coated with a 30 nm gold (Au) layer on top of 3 nm of chromium (Cr), which emits electrons by means of single-photon photoemission when femtosecond pulses in the near ultraviolet (257 nm) are fed into the fiber on the air side. The emission area can be adjusted to any value between a few nanometers (using tapered fibers) and the size of a multi-mode fiber core (100 μm or larger). In this proof-of-principle experiment, two different types of fibers were tested, with emission spot diameters of 50 μm and 100 μm, respectively. The normalized thermal electron beam emittance (TE) was measured by means of the aperture scan technique, and a TE of 4.0 π nm was measured for the smaller spot diameter. Straightforward enhancements to the concept allowed to demonstrate operation in an electric field environment of up to 7 MV/m.

  20. Solid phase extraction of proteins from buffer solutions employing capillary-channeled polymer (C-CP) fibers as the stationary phase.

    PubMed

    Burdette, Carolyn Q; Marcus, R Kenneth

    2013-02-21

    Polypropylene (PP) capillary-channeled polymer (C-CP) fibers are applied for solid phase extraction (SPE) of proteins from aqueous buffer solutions using a micropipette tip-based format. A process was developed in which centrifugation is used as the moving force for solution passage in the loading/washing steps instead of the previously employed manual aspiration. The complete procedure requires ~15 minutes, with the number of samples run in parallel limited only by the capacity of the centrifuge. The method performance was evaluated based on adsorption and elution characteristics of several proteins (cytochrome c, lysozyme, myoglobin, and glucose oxidase) from 150 mM phosphate buffered saline (PBS) solutions. Protein concentration ranges of ~2 to 100 μg mL(-1) were employed and the recovery characteristics determined through UV-Vis absorbance spectrophotometry for protein quantification. The protein loading capacities across the range of proteins was ~1.5 μg for the 5 mg fiber tips. Average recoveries from PBS were determined for each protein sample; cytochrome c ~86%, lysozyme ~80%, myoglobin ~86%, and glucose oxidase ~89%. Recoveries from more complex matrices, synthetic urine and synthetic saliva, were determined to be ~90%. A 10× dilution study for a fixed 1 μg protein application yielded 94 ± 3.2% recoveries. The C-CP tips provided significantly higher recoveries for myoglobin in a 150 mM PBS matrix in comparison to a commercially available protein SPE product, with the added advantages of low cost, rapid processing, and reusability.

  1. Effect of Green Tea Extract Encapsulated Into Chitosan Nanoparticles on Hepatic Fibrosis Collagen Fibers Assessed by Atomic Force Microscopy in Rat Hepatic Fibrosis Model.

    PubMed

    Safer, Abdel-Majeed A; Hanafy, Nomany A; Bharali, Dhruba J; Cui, Huadong; Mousa, Shaker A

    2015-09-01

    The present study examined the effect of Green Tea Extract (GTE) encapsulated into Chitosan Nanoparticles (CS-NPs) on hepatic fibrosis in rat model as determined by atomic force microscopy (AFM). The bioactive compounds in GTE encapsulated into CS-NPs were determined using LC-MS/MS method. Additionally, the uptake of GTE-CS NPs in HepG2 cells showed enhanced uptake. In experimental fibrosis model, AFM was used as a high resolution microscopic tool to investigate collagen fibers as an indicator of hepatic fibrosis induced by treatment with CCl4. Paraffin sections of fibrotic liver tissues caused by CC4 treatment of rats and the effect of GTE-CS NPs treatment with or without CCl4 on hepatic fibrosis were examined. Liver tissues from the different groups of animals were de-waxed and processed as for normal H/E staining and Masson's trichrome staining to locate the proper area of ECM collagen in the CCl4 group versus collagen in liver tissues treated with the GTE-CS NPs with or without CCl4. Selected areas of paraffin sections were trimmed off and fixed flat on top of mica and inserted in the AFM stage. H/E staining, Masson's trichrome stained slides, and AFM images revealed that collagen fibers of 250 to 300 nm widths were abundant in the fibrotic liver samples while those of GTE-CS NPs were clear as in the control group. Data confirmed the hypothesis that GTE-CS NPs are effective in removing all the extracellular collagen caused by CCl4 in the hepatic fibrosis rat liver.

  2. Six mode selective fiber optic spatial multiplexer.

    PubMed

    Velazquez-Benitez, A M; Alvarado, J C; Lopez-Galmiche, G; Antonio-Lopez, J E; Hernández-Cordero, J; Sanchez-Mondragon, J; Sillard, P; Okonkwo, C M; Amezcua-Correa, R

    2015-04-15

    Low-loss all-fiber photonic lantern (PL) mode multiplexers (MUXs) capable of selectively exciting the first six fiber modes of a multimode fiber (LP01, LP11a, LP11b, LP21a, LP21b, and LP02) are demonstrated. Fabrication of the spatial mode multiplexers was successfully achieved employing a combination of either six step or six graded index fibers of four different core sizes. Insertion losses of 0.2-0.3 dB and mode purities above 9 dB are achieved. Moreover, it is demonstrated that the use of graded index fibers in a PL eases the length requirements of the adiabatic tapered transition and could enable scaling to large numbers.

  3. Microwave sidebands for laser cooling by direct modulation of a tapered amplifier

    NASA Astrophysics Data System (ADS)

    Mahnke, J.; Kulas, S.; Geisel, I.; Jöllenbeck, S.; Ertmer, W.; Klempt, C.

    2013-06-01

    Laser cooling of atoms usually necessitates several laser frequencies. Alkaline atoms, for example, are cooled by two lasers with a frequency difference in the gigahertz range. This gap cannot be closed with simple shifting techniques. Here, we present a method of generating sidebands at 6.6 GHz by modulating the current of a tapered amplifier, which is seeded by an unmodulated master laser. The sidebands enable trapping of 1.1 × 109 87Rb atoms in a chip-based magneto-optical trap. Compared to the direct modulation of the master laser, this method allows for an easy implementation, a fast adjustment over a wide frequency range, and the simultaneous extraction of unmodulated light for manipulation and detection. The low power consumption, small size, and applicability for multiple frequencies benefit a wide range of applications reaching from atom-based mobile sensors to the laser cooling of molecules.

  4. Bragg gratings in surface-core fibers: Refractive index and directional curvature sensing

    NASA Astrophysics Data System (ADS)

    Osório, Jonas H.; Oliveira, Ricardo; Aristilde, Stenio; Chesini, Giancarlo; Franco, Marcos A. R.; Nogueira, Rogério N.; Cordeiro, Cristiano M. B.

    2017-03-01

    In this paper, we report, to our knowledge, the first extended study of the inscription of Bragg gratings in surface-core fibers and their application in refractive index and directional curvature sensing. The research ranges from fiber fabrication and grating inscription in untapered and tapered fibers to the performance of simulations and sensing measurements. Maximum sensitivities of 40 nm/RIU and 202.7 pm/m-1 were attained in refractive index and curvature measurements respectively. The obtained results compares well to other fiber Bragg grating based devices. Ease of fabrication, robustness and versatility makes surface-core fibers an interesting platform when exploring fiber sensing devices.

  5. Piezoelectric energy harvester having planform-tapered interdigitated beams

    DOEpatents

    Kellogg, Rick A.; Sumali, Hartono

    2011-05-24

    Embodiments of energy harvesters have a plurality of piezoelectric planform-tapered, interdigitated cantilevered beams anchored to a common frame. The plurality of beams can be arranged as two or more sets of beams with each set sharing a common sense mass affixed to their free ends. Each set thus defined being capable of motion independent of any other set of beams. Each beam can comprise a unimorph or bimorph piezoelectric configuration bonded to a conductive or non-conductive supporting layer and provided with electrical contacts to the active piezoelectric elements for collecting strain induced charge (i.e. energy). The beams are planform tapered along the entirety or a portion of their length thereby increasing the effective stress level and power output of each piezoelectric element, and are interdigitated by sets to increase the power output per unit volume of a harvester thus produced.

  6. Design of MR brake featuring tapered inner magnetic core

    NASA Astrophysics Data System (ADS)

    Sohn, Jung Woo; Oh, Jong-Soek; Choi, Seung-Bok

    2015-04-01

    In this work, a new type of MR brake featuring tapered inner magnetic core is proposed and its braking performance is numerically evaluated. In order to achieve high braking torque with restricted size and weight of MR brake system, tapered inner magnetic core is designed and expands the area that the magnetic flux is passing by MR fluid-filled gap. The mathematical braking torque model of the proposed MR brake is derived based on the field-dependent Bingham rheological model of MR fluid. Finite element analysis is carried out to identify electromagnetic characteristics of the conventional and the proposed MR brake configuration. To demonstrate the superiority of the proposed MR brake, the braking torque of the proposed MR brake is numerically evaluated and compared with that of conventional MR brake model.

  7. Free-electron lasers with very slow wiggler taper

    NASA Astrophysics Data System (ADS)

    Bosley, D. L.; Kevorkian, J.

    1990-09-01

    A highly accurate, explicit asymptotic solution of the electron energy and phase is found for a class of free-electron lasers with very long wavelength beams, very low electron energies, and very slow taper of the wiggler field relative to the wiggler period. Dimensionless variables are defined and normalized, and three small parameters which characterize the operation of the FEL are identified. Because of the explicit nature of the solution, our results may be directly used to calculate features such as the escape distance of the electron from the potential well and the effects of the various physical parameters. One important advantage of the very slow wiggler taper is the increased efficiency of the energy transfer from the electron beam to the signal field due to increased bucket width. Numerical calculations are performed to verify all results.

  8. Free-electron lasers with very slow wiggler taper

    NASA Astrophysics Data System (ADS)

    Bosley, D. L.; Kevorkian, J.

    1991-04-01

    A highly accurate, explicit asymptotic solution of the electron energy and phase is found for a class of free-electron lasers (FELs) with very long wavelength beams, very low electron energies, and very slow taper of the wiggler field relative to the wiggler period. Dimensionless variables are defined and normalized, and three small parameters which characterize the operation of the FEL are identified. Due to the explicit asymptotic nature of the solution, the results may be directly used to calculate features such as the escape distance of the electron from the potential well and the effects of the various physical parameters. One important advantage of the very slow wiggler taper is the increased efficiency of the energy transfer from the electron beam to the signal field due to increased bucket width. Numerical calculations are performed to verify all results.

  9. Development of high-power gyrotrons with gradually tapered cavity

    SciTech Connect

    Lei Chaojun; Yu Sheng; Niu Xinjian; Liu Yinghui; Li Hongfu; Li Xiang

    2012-12-15

    In high power gyrotrons, the parasitic modes coupled with the operating mode cannot be avoided in the beam-wave interaction. These parasitic modes will decrease the efficiency of the gyrotrons. The purity of the operating mode affected by different tapers should be carefully studied. The steady-state self-consistent nonlinear theory for gyrotron with gradually tapered cavity is developed in this paper. A steady-state calculation code including 'cold cavity' and 'hot cavity' is designed. By comparison, a time-domain model analysis of gyrotron operation is also studied by particle-in-cell (PIC). It is found that the tapers of gyrotron have different influences on the modes coupling between the operating mode and the parasitic modes. During the study, an example of 94 GHz gyrotron with pure operating mode TE{sub 03} has been designed. The purity of the operating mode in the optimized cavity is up to -77 dB, and in output waveguide of the cavity is up to -76 dB. At the same time, the beam-wave interaction in the designed cavity has been simulated, too. An output power of 120 kW, corresponding to 41.6% efficiency and an oscillation frequency of 94.099 GHz have been achieved with a 50 kV, 6 A helical electron beam at a guiding magnetic field of 3.5485 T. The results show that the power in spurious modes of the optimized cavity may be kept far below than that of the traditional tapered cavity.

  10. Gas insulated transmission line having tapered particle trapping ring

    DOEpatents

    Cookson, Alan H.

    1982-01-01

    A gas-insulated transmission line includes an outer sheath, an inner conductor, insulating supports and an insulating gas. A particle-trapping ring is secured to each insulating support, and it is comprised of a central portion and two tapered end portions. The ends of the particle trapping ring have a smaller diameter than the central portion of the ring, so as to enable the use of the particle trapping ring in a curved transmission line.

  11. Schottky photodetector with tapered thin metal strip on silicon waveguide

    NASA Astrophysics Data System (ADS)

    Guo, Jingshu; Wu, Zhiwei; Li, Yuan; Zhao, Yanli

    2016-01-01

    We propose a Schottky photodetector with tapered thin metal strip on SOI platform. Schottky photodetector can detect photons below the semiconductor bandgap energy by exploiting the internal photoemission. In the internal photoemission process, the hot carriers generate in the tapered thin metal strip where light absorption occurs, and part of these carriers can be emitted over the Schottky barrier and collected as photocurrent. The small thickness of the tapered metal strip contributes to a high internal quantum efficiency of 11.25%. This metal-semiconductor structure acts as a photonics-plasmonics mode convertor. According to 3D-FDTD simulation, about 95.8% of the incident optical power can be absorbed in the absorption area within 4.5μm at wavelength of 1550 nm. The responsivity is estimated to be 0.135A/W at 1550 nm. This compact design with a low dark current has a minimum detectable power of -23.15 dβm. We argue that this design can promote the progress of all-Si photo-detection in near-infrared communication band.

  12. A woman's experience of tapering from buprenorphine during pregnancy

    PubMed Central

    Welle-Strand, Gabrielle Katrine; Kvamme, Odd; Andreassen, Andreas; Ravndal, Edle

    2014-01-01

    Although opioid maintenance treatment (OMT) is the treatment of choice for pregnant opioid-dependent patients, some professionals argue that tapering the medication dose will reduce the severity of neonatal abstinence syndrome (NAS). This case description is based on the patient's detailed blog, and medical records from her general practitioner and the hospital. The patient is an employed, 32-year-old drug-abstinent woman in OMT. Her taper from 24 mg of buprenorphine started at 14 weeks’ gestation and is slow, with withdrawal symptoms increasing gradually. In pregnancy week 31, she is off buprenorphine but she has severe withdrawal symptoms. She chose to go back on 4 mg of buprenorphine. The patient's son was born in pregnancy week 38+3, weighs 2950 g and does not require pharmacological treatment for NAS. The fetus most probably did experience fetal stress during the patient's tapering. It was the right decision by the patient to go back on buprenorphine. PMID:25540212

  13. Reconfigurable tapered coaxial slot antenna for hepatic microwave ablation.

    PubMed

    Malhotra, Neeru; Marwaha, Anupma; Kumar, Ajay

    2016-01-01

    Microwave ablation is rapidly being rediscovered and developed for treating many cancers of liver, lung, kidney and bone, as well as arrhythmias and other medical conditions. The microwaves ablate tissue by heating it to cytotoxic temperatures. The microwave antenna design suffers the challenges of effective coupling and penetration into body tissues, uncontrolled power deposition due to applicator construction limitations affecting uniform heating of target region, and narrowband operation leading to mismatch for many patients and detrimental heating. To meet out the requirements of wideband operation and localized lesion reconfigurable linearly tapered slot interstitial wideband antenna has been proposed for working in the 1.38 GHz to 4.31 GHz frequency band. The performance of the antenna is evaluated by using FEM-based HFSS software. The slot height and taper height are reconfigured for parametric analysis achieving maximum impedance matching and spherical ablation zone without requiring any additional adjustable structures. The tapering of the slot in coaxial antenna generates current distribution at the edges of the slot for maximizing specific absorption rate.

  14. Critical Coupling Between Optical Fibers and WGM Resonators

    NASA Technical Reports Server (NTRS)

    Matsko, Andrey; Maleki, Lute; Itchenko, Vladimir; Savchenkov, Anatoliy

    2009-01-01

    Two recipes for ensuring critical coupling between a single-mode optical fiber and a whispering-gallery-mode (WGM) optical resonator have been devised. The recipes provide for phase matching and aperture matching, both of which are necessary for efficient coupling. There is also a provision for suppressing intermodal coupling, which is detrimental because it drains energy from desired modes into undesired ones. According to one recipe, the tip of the single-mode optical fiber is either tapered in diameter or tapered in effective diameter by virtue of being cleaved at an oblique angle. The effective index of refraction and the phase velocity at a given position along the taper depend on the diameter (or effective diameter) and the index of refraction of the bulk fiber material. As the diameter (or effective diameter) decreases with decreasing distance from the tip, the effective index of refraction also decreases. Critical coupling and phase matching can be achieved by placing the optical fiber and the resonator in contact at the proper point along the taper. This recipe is subject to the limitation that the attainable effective index of refraction lies between the indices of refraction of the bulk fiber material and the atmosphere or vacuum to which the resonator and fiber are exposed. The other recipe involves a refinement of the previously developed technique of prism coupling, in which the light beam from the optical fiber is collimated and focused onto one surface of a prism that has an index of refraction greater than that of the resonator. Another surface of the prism is placed in contact with the resonator. The various components are arranged so that the collimated beam is focused at the prism/resonator contact spot. The recipe includes the following additional provisions:

  15. High-power monolithic fiber amplifiers based on advanced photonic crystal fiber designs

    NASA Astrophysics Data System (ADS)

    Sipes, Donald L.; Tafoya, Jason D.; Schulz, Daniel S.; Alkeskjold, Thomas Tanggaard; Weirich, Johannes; Olausson, Christina B.

    2014-03-01

    We report on the development and performance of a fully monolithic PCF amplifier that has achieved over 400 W with near diffraction limited beam quality with an approximately 1GHz phase modulated input. The key components for these amplifiers are an advanced PCF fiber design that combines segmented acoustically tailored (SAT) fiber that is gain tailored, a novel multi fiber-coupled laser diode stack and a monolithic 6+1x1 large fiber pump/signal multiplexer. The precisely aligned 2-D laser diode emitter array found in laser diode stacks is utilized by way of a simple in-line imaging process with no mirror reflections to process a 2-D array of 380-450 elements into 3 400/440μm 0.22NA pump delivery fibers. The fiber combiner is an etched air taper design that transforms low numerical aperture (NA), large diameter pump radiation into a high NA, small diameter format for pump injection into an air-clad large mode area PCF, while maintaining a constant core size through the taper for efficient signal coupling and throughput. The fiber combiner has 6 400/440/0.22 core/clad/NA pump delivery fibers and a 25/440 PM step-index signal delivery fiber on the input side and a 40/525 PM undoped PCF on the output side. The etched air taper transforms the six 400/440 μm 0.22 NA pump fibers to the 525 μm 0.55 NA core of the PCF fiber with a measured pump combining efficiency of over 95% with a low brightness drop. The combiner also operates as a stepwise mode converter via a 30 μm intermediate core region in the combiner between the 20 μm core of the input fiber and the 40 μm fiber core of the PCF with a measured signal efficiency of 60% to 70% while maintaining polarization with a measured PER of 20 dB. These devices were integrated in to a monolithic fiber amplifier with high efficiency and near diffraction limited beam quality.

  16. Autoresonant four-wave mixing in optical fibers

    SciTech Connect

    Yaakobi, O.; Friedland, L.

    2010-08-15

    A theory of autoresonant four-wave mixing in tapered fibers is developed in application to optical parametric amplification (OPA). In autoresonance, the interacting waves (two pump waves, a signal, and an idler) stay phase-locked continuously despite variation of system parameters (spatial tapering). This spatially extended phase-locking allows complete pump depletion in the system and uniform amplification spectrum in a wide frequency band. Different aspects of autoresonant OPA are described including the automatic initial phase-locking, conditions for autoresonant transition, stability, and spatial range of the autoresonant interaction.

  17. A solid-phase microextraction platinized stainless steel fiber coated with a multiwalled carbon nanotube-polyaniline nanocomposite film for the extraction of thymol and carvacrol in medicinal plants and honey.

    PubMed

    Ghiasvand, Alireza; Dowlatshah, Samira; Nouraei, Nadia; Heidari, Nahid; Yazdankhah, Fatemeh

    2015-08-07

    A mechanically hard and cohesive porous fiber, with large surface area, for more strong attachment of the coating was provided by platinizing a stainless steel wire. Then, the platinized stainless steel fiber was coated with a multiwalled carbon nanotube/polyaniline (MWCNT/PANI) nanocomposite using electrophoretic deposition (EPD) method and applied for the extraction of thymol and carvacrol with direct-immersion solid-phase microextraction (DI-SPME) method followed by high-performance liquid chromatography-ultraviolet detection (HPLC-UV) quantification. To provide a larger coarse surface for the tightened attachment of coating on the fiber, a stainless steel wire was platinized using a suitable optimized EPD method. Different experimental parameters were studied and the optimal conditions were obtained as: pH of the sample solution: 2; extraction time: 60min; salt content in the sample solution: 1% w/v NaNO3; desorption time: 60min; type and volume of the desorption solvent: acetonitrile, 100μL. Under the optimized conditions, limits of detection (LODs) were 0.6 and 0.8μgmL(-1) for thymol and carvacrol, respectively. Linear dynamic range (LDR) for the calibration curves of both analytes were 1-80μgmL(-1). Relative standard deviation (RSD%, n=6) was 6.8 for thymol and 12.7 for carvacrol. The proposed fiber was successfully applied for the recovery and determination of thymol and carvacrol in thyme, savory, and honey samples.

  18. Thulium Fiber Laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Blackmon, Richard Leious, Jr.

    The Thulium Fiber Laser (TFL) has been studied as a potential alternative to the conventional Holmium:YAG laser (Ho:YAG) for the treatment of kidney stones. The TFL is more ideally suited for laser lithotripsy because of the higher absorption coefficient of the emitted wavelength in water, the superior Gaussian profile of the laser beam, and the ability to operate at arbitrary temporal pulse profiles. The higher absorption of the TFL by water helps translate into higher ablation of urinary stones using less energy. The Gaussian spatial beam profile allows the TFL to couple into fibers much smaller than those currently being used for Ho:YAG lithotripsy. Lastly, the ability of arbitrary pulse operation by the TFL allows energy to be delivered to the stone efficiently so as to avoid negative effects (such as burning or bouncing of the stone) while maximizing ablation. Along with these improvements, the unique properties of the TFL have led to more novel techniques that have currently not been used in the clinic, such as the ability to control the movement of stones based on the manner in which the laser energy is delivered. Lastly, the TFL has led to the development of novel fibers, such as the tapered fiber and removable tip fiber, to be used for lithotripsy which can lead to safer and less expensive treatment of urinary stones. Overall, the TFL has been demonstrated as a viable alternative to the conventional Ho:YAG laser and has the potential to advance methods and tools for treatment of kidney stones.

  19. Microfiber Fabry-Perot interferometer fabricated by taper-drawing technique and its application as a radio frequency interrogated refractive index sensor.

    PubMed

    Zhang, Jiejun; Sun, Qizhen; Liang, Ruibing; Wo, Jianghai; Liu, Deming; Shum, Perry

    2012-07-15

    We propose a novel fiber Fabry-Perot interferometer (FPI) that incorporates a length of microfiber as its cavity and two fiber Bragg gratings (FBGs) as reflectors. The microfiber FPI is simply fabricated by flame-heated taper-drawing the central spot of an FBG into a section of microfiber. Ambient refractive index (RI) influences the effective index of microfiber, and thus the free spectrum range of the microfiber FPI, resulting in RI sensing. A dual-wavelength fiber laser based on the microfiber FPI is constructed, enabling radio frequency interrogation with high resolution. RI sensitivity of 911 MHz/RIU is experimentally demonstrated for microfiber FPI with equivalent diameter of 1.455 μm. Simulation results indicate that the sensitivity can be further enhanced by reducing the diameter of the microfiber.

  20. Ultra-low power fiber-coupled gallium arsenide photonic crystal cavity electro-optic modulator.

    PubMed

    Shambat, Gary; Ellis, Bryan; Mayer, Marie A; Majumdar, Arka; Haller, Eugene E; Vučković, Jelena

    2011-04-11

    We demonstrate a gallium arsenide photonic crystal cavity injection-based electro-optic modulator coupled to a fiber taper waveguide. The fiber taper serves as a convenient and tunable waveguide for cavity coupling with minimal loss. Localized electrical injection of carriers into the cavity region via a laterally doped p-i-n diode combined with the small mode volume of the cavity enable ultra-low energy modulation at sub-fJ/bit levels. Speeds of up to 1 GHz are demonstrated with photoluminescence lifetime measurements revealing that the ultimate limit goes well into the tens of GHz.

  1. Computationally generated velocity taper for efficiency enhancement in a coupled-cavity traveling-wave tube

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.

    1989-01-01

    A computational routine has been created to generate velocity tapers for efficiency enhancement in coupled-cavity TWTs. Programmed into the NASA multidimensional large-signal coupled-cavity TWT computer code, the routine generates the gradually decreasing cavity periods required to maintain a prescribed relationship between the circuit phase velocity and the electron-bunch velocity. Computational results for several computer-generated tapers are compared to those for an existing coupled-cavity TWT with a three-step taper. Guidelines are developed for prescribing the bunch-phase profile to produce a taper for efficiency. The resulting taper provides a calculated RF efficiency 45 percent higher than the step taper at center frequency and at least 37 percent higher over the bandwidth.

  2. Key findings from studies of methotrexate tapering and withdrawal in rheumatoid arthritis.

    PubMed

    Subesinghe, Sujith; Scott, Ian C

    2015-01-01

    Methotrexate is the dominant initial drug in the management of rheumatoid arthritis (RA). Despite its widespread use, methotrexate is associated with a number of adverse effects. Tapering its dose to the minimal amount required to maintain RA remission is, therefore, an important clinical goal. While the complete withdrawal of disease-modifying anti-rheumatic drugs is associated with a definite risk of a disease flare, it is unclear as to what the risk is specific to methotrexate withdrawal and whether this can be minimized by gradual dose reduction (termed 'tapering'). This review examines studies of methotrexate tapering and withdrawal on RA outcomes. It covers three scenarios: tapering/withdrawing methotrexate monotherapy; tapering/withdrawing methotrexate as part of a 'step-down' combination disease-modifying anti-rheumatic drug regimen; and tapering/withdrawing methotrexate when it is being co-prescribed with biologic agents.

  3. Fiber optic probe having fibers with endfaces formed for improved coupling efficiency and method using same

    DOEpatents

    O'Rourke, Patrick E.; Livingston, Ronald R.

    1995-01-01

    A fiber optic probe for detecting scattered light, with transmitting and receiving fibers having slanted ends and bundled together to form a bevel within the tip of the probe. The probe comprises a housing with a transparent window across its tip for protecting the transmitting and receiving fibers held therein. The endfaces of the fibers are slanted, by cutting, polishing and the like, so that they lie in a plane that is not perpendicular to the longitudinal axis of the respective fiber. The fibers are held in the tip of the probe using an epoxy and oriented so that lines normal to the slanted endfaces are divergent with respect to one another. The epoxy, which is positioned substantially between the transmitting and receiving fibers, is tapered so that the transmitting fiber, the epoxy and the receiving fiber form a bevel of not more than 20 degrees. The angled fiber endfaces cause directing of the light cones toward each other, resulting in improved light coupling efficiency. A light absorber, such as carbon black, is contained in the epoxy to reduce crosstalk between the transmitting and receiving fibers.

  4. Fiber optic probe having fibers with endfaces formed for improved coupling efficiency and method using same

    DOEpatents

    O`Rourke, P.E.; Livingston, R.R.

    1995-03-28

    A fiber optic probe is disclosed for detecting scattered light, with transmitting and receiving fibers having slanted ends and bundled together to form a bevel within the tip of the probe. The probe comprises a housing with a transparent window across its tip for protecting the transmitting and receiving fibers held therein. The endfaces of the fibers are slanted, by cutting, polishing and the like, so that they lie in a plane that is not perpendicular to the longitudinal axis of the respective fiber. The fibers are held in the tip of the probe using an epoxy and oriented so that lines normal to the slanted endfaces are divergent with respect to one another. The epoxy, which is positioned substantially between the transmitting and receiving fibers, is tapered so that the transmitting fiber, the epoxy and the receiving fiber form a bevel of not more than 20 degrees. The angled fiber endfaces cause directing of the light cones toward each other, resulting in improved light coupling efficiency. A light absorber, such as carbon black, is contained in the epoxy to reduce crosstalk between the transmitting and receiving fibers. 3 figures.

  5. Detachable fiber optic tips for use in thulium fiber laser lithotripsy.

    PubMed

    Hutchens, Thomas C; Blackmon, Richard L; Irby, Pierce B; Fried, Nathaniel M

    2013-03-01

    The thulium fiber laser (TFL) has recently been proposed as an alternative to the Holmium:YAG (Ho:YAG) laser for lithotripsy. The TFL's Gaussian spatial beam profile provides higher power transmission through smaller optical fibers with reduced proximal fiber tip damage, and improved saline irrigation and flexibility through the ureteroscope. However, distal fiber tip damage may still occur during stone fragmentation, resulting in disposal of the entire fiber after the procedure. A novel design for a short, detachable, distal fiber tip that can fit into an ureteroscope's working channel is proposed. A prototype, twist-lock, spring-loaded mechanism was constructed using micromachining methods, mating a 150-μm-core trunk fiber to 300-μm-core fiber tip. Optical transmission measuring 80% was observed using a 30-mJ pulse energy and 500-μs pulse duration. Ex vivo human calcium oxalate monohydrate urinary stones were vaporized at an average rate of 187  μg/s using 20-Hz modulated, 50% duty cycle 5 pulse packets. The highest stone ablation rates corresponded to the highest fiber tip degradation, thus providing motivation for use of detachable and disposable distal fiber tips during lithotripsy. The 1-mm outer-diameter prototype also functioned comparable to previously tested tapered fiber tips.

  6. Determining resin/fiber content of laminates

    NASA Technical Reports Server (NTRS)

    Garrard, G. G.; Houston, D. W.

    1979-01-01

    Article discusses procedure where hydrazine is used to extract graphite fibers from cured polyimide resin. Method does not attack graphite fibers and is faster than hot-concentrated-acid digestion process.

  7. Fabrication and characterization of periodically patterned silica fiber structures for enhanced second-order nonlinearity.

    PubMed

    Daengngam, Chalongrat; Kandas, Ishac; Ashry, Islam; Wang, Anbo; Heflin, James R; Xu, Yong

    2015-03-23

    We develop and characterize a UV ablation technique that can be used to pattern soft materials such as polymers and nonlinear molecules self-assembled over silica microstructures. Using this method, we fabricate a spatially periodic coating of nonlinear film over a thin silica fiber taper for second harmonic generation (SHG). Experimentally, we find that the second harmonic signal produced by the taper with periodic nonlinear coating is 15 times stronger than the same taper with uniform nonlinear coating, which suggests that quasi-phase-matching is at least partially achieved in the patterned nonlinear silica taper. The same technique can also be used to spatially pattern other types of functional nanomaterials over silica microstructures with curved surfaces, as demonstrated by deposition of gold nanoparticles in patterned structures.

  8. Bend-insensitive fiber based vibration sensor

    NASA Astrophysics Data System (ADS)

    Xu, Yanping; Lu, Ping; Baset, Farhana; Bhardwaj, Vedula Ravi; Bao, Xiaoyi

    2014-05-01

    We report two novel fiber-optic vibration sensors based on standard telecom bend-insensitive fiber (BIF). A tapered BIF forming a fiber Mach-Zehnder interferometer could measure continuous and damped vibration from 1 Hz up to 500 kHz. An enclosed microcantilever is fabricated inside the BIF by chemical etching and fusion spliced with a readout singlemode fiber that exhibits a frequency range from 5 Hz to 10 kHz with high signal-to-noise ratio (SNR) up to 68 dB. The unique double cladding structure of the BIF ensures both sensors with advantages of compactness, high resistance to the external disturbance and stronger mechanical strength.

  9. Quantitative comparison of calcium hydroxide removal by EndoActivator, ultrasonic and ProTaper file agitation techniques: an in vitro study.

    PubMed

    Khaleel, Huda Yasir; Al-Ashaw, Ahmed Jawad; Yang, Yan; Pang, Ai-hui; Ma, Jing-zhi

    2013-02-01

    Calcium hydroxide (CH) dressing residues can compromise endodontic sealing. This study aimed to evaluate the amount of remaining CH in root canals after mechanical removal by four groups of irrigation techniques including needle irrigation only, ProTaper file, EndoActivator, and ultrasonic file. Fifteen extracted single-rooted teeth were collected and used for all four groups. The samples were firstly prepared by ProTaper rotary instruments, and then sectioned longitudinally through the long axis of the root canals, followed by final reassembling by wires. CH was kept in the canals for 7 days setting. The removal procedure began with 5 mL of 2.5% sodium hypochlorite (NaOCl) followed by 1 mL of 17% ethylenediaminetetraacetic acid and a final irrigation with 5 mL of 2.5% NaOCl solution for all groups. No additional agitation of the irrigant was performed in group 1, while agitation for 20 s between irrigants was done with F2 ProTaper rotary file in group 2, EndoActivator with tip size 25/.04 in group 3 and by an ultrasonic file 25/.02 in group 4. The total activation time was 60 s. The roots were then disassembled and captured by digital camera. The ratio of CH coated surface area to the surface area of the whole canal as well as each third of the canal was calculated. The data were statistically analyzed by one-way ANOVA using post hoc Tukey test. Results showed that none of the four techniques could remove all CH. No significant difference was found between EndoActivator and ultrasonic techniques. However, they both removed significantly more CH than ProTaper and needle irrigation (P=0.0001). In conclusion, the sonic and ultrasonic agitation techniques were more effective in removing intracanal medicaments than the ProTaper rotary file and needle irrigation in all thirds of the canal.

  10. Efficiency and Spectrum Enhancement in a Tapered Free-Electron Laser Amplifier

    SciTech Connect

    Wang, X. J.; Harder, D.; Murphy, J. B.; Qian, H.; Shen, Y.; Yang, X.; Freund, H. P.; Miner, W. H. Jr.

    2009-10-09

    We report the first experimental characterization of efficiency and spectrum enhancement in a laser-seeded free-electron laser using a tapered undulator. Output and spectra in the fundamental and third harmonic were measured versus distance for uniform and tapered undulators. With a 4% field taper over 3 m, a 300% (50%) increase in the fundamental (third harmonic) output was observed. A significant improvement in the spectra with the elimination of sidebands was observed using a tapered undulator. The experiment is in good agreement with predictions using the MEDUSA simulation code.

  11. Coupled-Cavity Traveling-Wave Tube Has Phase-Adjusted Taper

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.

    1992-01-01

    In structure of improved coupled-cavity traveling-wave tube amplifier, lengths of cavities chosen according to computer-generated, nonlinear taper to increase efficiency of conversion of power from electron beam to microwave. Design calls for "phase-adjusted taper," calculated so phase of electron bunches with respect to phase of microwave changes gradually from value conducive to formation of strong bunches to value conducive to strong transfer of power to microwave at output of taper. Phase-adjusted taper significantly increases power capability of microwave transmission, enabling satellite-communication systems to have higher data-transmission rates.

  12. Efficiency enhancement of coupled-cavity TWT's through cavity resonance tapering

    NASA Technical Reports Server (NTRS)

    Connolly, D. J.

    1979-01-01

    The paper examines efficiency enhancement of coupled-cavity traveling-wave tube (TWT) through cavity resonance tapering. Beam-wave resynchronization through circuit velocity reduction is used for TWT efficiency enhancement, with circuit velocity reduction in coupled cavity TWT's accomplished through period tapering. However, the amount of the latter is limited by the stability considerations, so that beyond a critical value of velocity reduction, the tube may be subject to zero drive oscillations originating in the velocity taper region. The coupled-cavity resonance tapering allows the velocity reduction to continue beyond the limit of stable period tapering, and it is accomplished by a gradual reduction in the cavity resonance frequency, with the period and the circuit bandwidth unchanged. The advantages of cavity resonance tapering vs period tapering are discussed, and test data are presented with the results of large-signal computer calculations. It is shown that cavity resonance tapering can produce efficiencies as period tapering without incurring the same risk of lower band-edge oscillations.

  13. Fabrication and characterization of an optical fiber probe for esophageal pressure measurements

    NASA Astrophysics Data System (ADS)

    Romolini, A.; Falciai, Riccardo; Schena, Alessandro

    1996-11-01

    A miniaturized optical fiber probe for measuring the esophageal pressure, making use of biconically tapered fibers, has been built and characterized. The operation of the probe is based on the decrease of the transmitted power from a biconical fiber when it is bent, in its biconical part, under the action of pressure. The necessary sensitivity is about 1 divided by 2 mm Hg in the range between 0 and 50 mm Hg. To obtain it we have fabricated and tested some probes using different fibers (four-mode, two- mode and monomode) and different values of tapering. Our best result has been achieved with a probe made with a monomode fiber of waist 36 micrometer whose sensitivity is 2 mm Hg in the range between 5 and 55 mm Hg.

  14. Flexibility of K3 and ProTaper universal instruments.

    PubMed

    Grazziotin-Soares, Renata; Barato Filho, Flares; Vanni, José Roberto; Almeida, Susimara; Oliveira, Elias Pandonor Motcy de; Barletta, Fernando Branco; Limongi, Orlando

    2011-01-01

    This study used a mechanical test to evaluate the flexibility of instruments from the K3 (conicity 0.04) and the ProTaper Universal systems when they were new and after 5 uses in simulated canals. Five sets of instruments of each system were tested: K3 (15, 20, 25, 30, 35, 40 and 45) and ProTaper Universal (S1, S2, F1, F2, F3, F4 and F5). Each set of instruments was used to prepare a simulated canal and the same set of instruments was used 5 times (50 canals). The number of each subgroup represented the number of uses: 0 (control), 1, 3 and 5 uses. Before and after each use, the instruments were submitted to a mechanical flexibility test performed in a Versat 502 universal testing machine. Interactions between the instrument and the number of uses were analyzed by ANOVA and Tukey's test at a 5% level of significance. Instruments from both systems presented lower flexibility after the third use compared to the flexibility obtained after uses 0 and 1 (p<0.05), and maintained the same flexibility after the fifth use. The flexibility of instruments from the K3 system decreased with the increase of diameter, irrespective of the number of uses. Among the instruments from the ProTaper Universal system, the shaping files presented greater flexibility than the finishing files. F2 and F3 were the least flexible instruments, and F4 and F5 presented flexibility values similar to those of F1.

  15. Liquid crystal optical fibers for sensing applications

    NASA Astrophysics Data System (ADS)

    Choudhury, P. K.

    2013-09-01

    Propagation characteristics of optical fibers are greatly dependent on materials, which the guides are comprised of. Varieties of materials have been developed and investigated for their usage in fabricating optical fibers for specific applications. Within the context, a liquid crystal medium is both inhomogeneous and optically anisotropic, and fibers made of such mediums are greatly useful. Also, liquid crystals exhibit strong electro-optic behavior, which allows alternation in their optical properties under the influence of external electric fields. These features make liquid crystal fibers greatly important for optical applications. The present communication is aimed at providing a glimpse of the efficacy of liquid crystals and/or fibers made of liquid crystals, followed by the analytical investigation of wave propagation through such guides. The sustainment of modes is explored in these fibers under varying fiber dimensions, and the novelty is discussed. The case of tapered liquid crystal fibers is also briefly discussed highlighting the usefulness. Control on the dispersion characteristics of such fibers may be imposed by making the guide even more complex; the possibility of devising such options is also touched upon.

  16. Automated on-fiber derivatization with headspace SPME-GC-MS-MS for the determination of primary amines in sewage sludge using pressurized hot water extraction.

    PubMed

    Llop, Anna; Pocurull, Eva; Borrull, Francesc

    2011-07-01

    An automated, environmentally friendly, simple, selective, and sensitive method was developed for the determination of ten primary aliphatic amines in sewage sludge at μg/kg dry weight (d.w.). The procedure involves a pressurized hot water extraction (PHWE) of the analytes from the solid matrix, followed by a fully automated on-fiber derivatization with 2,3,4,5-pentafluorobenzaldehyde (PFBAY) and headspace solid-phase microextraction (HS-SPME) and subsequent gas chromatography ion-trap tandem mass spectrometry (GC-IT-MS-MS) analysis. The limits of detection (LODs) of the method were between 0.5 and 45 μg/kg (d.w.) for all compounds except for ethyl-, isopropyl-, and amylamine, whose LODs were 70, 109, and 116 μg/kg (d.w.), respectively. The limits of quantification (LOQs) were between 10 and 350 μg/kg (d.w.). Repeatability and intermediate precision, expressed as RSD(%) (n=3), were lower than 18 and 21%, respectively. The method developed enabled to determine primary aliphatic amines in sludge from various urban and industrial sewage treatment plants as well as from a potable treatment plant. Most of the primary aliphatic amines were found in the sewage sludge samples analyzed corresponding to the maximum concentrations to the samples from the urban plant: for instance, isobutylamine and methylamine were found at 7728 and 12 536 μg/kg (d.w.), respectively. Amylamine was detected only in few samples but always at concentrations lower than its LOQ.

  17. Measurement of fiber orientation in short-fiber composites

    SciTech Connect

    Gonzalez, L.M.; Cumbrera, F.L.; Sanchez-Bajo, F.; Pajares, A. . Dept. de Fisica)

    1994-03-01

    The degree of fiber orientation in short-fiber composites plays an important role in determining many properties of these materials. In order to predict the toughening of a composite by using fiber reinforcements, the authors must consider the orientation of fibers as described probabilistically by the distribution function f([psi]), where [psi] is the angle which each fiber makes with the normal to the crack face. Here, a method for the characterization of the fiber orientation is built up in successive steps. In a first step the measurements of a planar array of fibers is afforded by extracting the important statistical information contained in a calculated Fraunhofer diffraction pattern of the fiber distribution. Subsequently, a method is proposed allowing us to derive the relevant f([psi]) distribution from the two-dimensional characterization of two orthogonal plane sections of the composite.

  18. Compound-taper feed horn for NASA 70-m antennas

    NASA Astrophysics Data System (ADS)

    Manshadi, Farzin; Hartop, Rob

    1988-09-01

    A novel X-band feedhorn was designed for the Deep Space Network (DSN) 70-meter antennas. The feedhorn is a compound-taper structure consisting of a corrugated flared section and a corrugated straight section. This feedhorn is designed to closely imitate the characteristics of the standard feedhorn, while providing the proper phase center location, without adding any significant loss to the system. The use of the existing feedhorn and the ease of manufacturing the corrugated straight section have resulted in major overall cost savings.

  19. Compound-taper feedhorn for the DSN 70-meter antennas

    NASA Astrophysics Data System (ADS)

    Manshadi, F.; Hartop, R.

    1987-08-01

    A novel X-band feedhorn was designed for the Deep Space Network (DSN) 70-meter antennas. The feedhorn is a compound-taper structure consisting of a corrugated flared section and a corrugated straight section. This feedhorn is designed to closely initiate the characteristics of the standard feedhorn, while providing the proper phase center location, without adding any significant loss to the system. The use of the existing feedhorn and the ease of manufacturing the corrugated straight section have resulted in major overall cost savings.

  20. Compound-taper feedhorn for the DSN 70-meter antennas

    NASA Technical Reports Server (NTRS)

    Manshadi, F.; Hartop, R.

    1987-01-01

    A novel X-band feedhorn was designed for the Deep Space Network (DSN) 70-meter antennas. The feedhorn is a compound-taper structure consisting of a corrugated flared section and a corrugated straight section. This feedhorn is designed to closely initiate the characteristics of the standard feedhorn, while providing the proper phase center location, without adding any significant loss to the system. The use of the existing feedhorn and the ease of manufacturing the corrugated straight section have resulted in major overall cost savings.

  1. Compound-taper feed horn for NASA 70-m antennas

    NASA Technical Reports Server (NTRS)

    Manshadi, Farzin; Hartop, Rob

    1988-01-01

    A novel X-band feedhorn was designed for the Deep Space Network (DSN) 70-meter antennas. The feedhorn is a compound-taper structure consisting of a corrugated flared section and a corrugated straight section. This feedhorn is designed to closely imitate the characteristics of the standard feedhorn, while providing the proper phase center location, without adding any significant loss to the system. The use of the existing feedhorn and the ease of manufacturing the corrugated straight section have resulted in major overall cost savings.

  2. Space Power Amplification with Active Linearly Tapered Slot Antenna Array

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1993-01-01

    A space power amplifier composed of active linearly tapered slot antennas (LTSA's) has been demonstrated and shown to have a gain of 30 dB at 20 GHz. In each of the antenna elements, a GaAs monolithic microwave integrated circuit (MMIC) three-stage power amplifier is integrated with two LTSA's. The LTSA and the MMIC power amplifier has a gain of 11 dB and power added efficiency of 14 percent respectively. The design is suitable for constructing a large array using monolithic integration techniques.

  3. Spatial frequency multiplier with active linearly tapered slot antenna array

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1994-01-01

    A frequency multiplier with active linearly tapered slot antennas (LTSA's) has been demonstrated at the second harmonic frequency. In each antenna element, a GaAs monolithic microwave integrated circuit (MMIC) distributed amplifier is integrated with two LTSA's. The multiplier has a very wide bandwidth and large dynamic range. The fundamental-to-second harmonic conversion efficiency is 8.1 percent. The spatially combined second harmonic signal is 50 dB above the noise level. The design is suitable for constructing a large array using monolithic integration techniques.

  4. Characterization of tapered slot antenna feeds and feed arrays

    NASA Technical Reports Server (NTRS)

    Kim, Young-Sik; Yngvesson, K. Sigfrid

    1990-01-01

    A class of feed antennas and feed antenna arrays used in the focal plane of paraboloid reflectors and exhibiting higher than normal levels of cross-polarized radiation in the diagonal planes is addressed. A model which allows prediction of element gain and aperture efficiency of the feed/reflector system is presented. The predictions are in good agreement with experimental results. Tapered slot antenna (TSA) elements are used an example of an element of this type. It is shown that TSA arrays used in multibeam systems with small beam spacings are competitive in terms of aperture efficiency with other, more standard types of arrays incorporating waveguide type elements.

  5. Modeling taper charge with a non-linear equation

    NASA Technical Reports Server (NTRS)

    Mcdermott, P. P.

    1985-01-01

    Work aimed at modeling the charge voltage and current characteristics of nickel-cadmium cells subject to taper charge is presented. Work reported at previous NASA Battery Workshops has shown that the voltage of cells subject to constant current charge and discharge can be modeled very accurately with the equation: voltage = A + (B/(C-X)) + De to the -Ex where A, B, D, and E are fit parameters and x is amp-hr of charge removed during discharge or returned during charge. In a constant current regime, x is also equivalent to time on charge or discharge.

  6. Design and Manufacture of Structurally Efficient Tapered Struts

    NASA Technical Reports Server (NTRS)

    Brewster, Jebediah W.

    2009-01-01

    Composite materials offer the potential of weight savings for numerous spacecraft and aircraft applications. A composite strut is just one integral part of the node-to-node system and the optimization of the shut and node assembly is needed to take full advantage of the benefit of composites materials. Lockheed Martin designed and manufactured a very light weight one piece composite tapered strut that is fully representative of a full scale flight article. In addition, the team designed and built a prototype of the node and end fitting system that will effectively integrate and work with the full scale flight articles.

  7. FEL Gain Length and Taper Measurements at LCLS

    SciTech Connect

    Ratner, Daniel; Brachmann, A.; Decker, F.J.; Ding, Y.; Dowell, D.; Emma, P.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, P.; Huang, Z.; Iverson, R.; Loos, H.; Miahnahri, A.; Nuhn, H.D.; Turner, J.; Welch, J.; White, W.; Wu, J.; Xiang, D.; Yocky, G.; /SLAC /LBL, Berkeley

    2010-07-30

    We present experimental studies of the gain length and saturation power level from 1.5 nm to 1.5 {angstrom} at the Linac Coherent Light Source (LCLS). By disrupting the FEL process with an orbit kick, we are able to measure the X-ray intensity as a function of undulator length. This kick method is cross-checked with the method of removing undulator sections. We also study the FEL-induced electron energy loss after saturation to determine the optimal taper of the undulator K values. The experimental results are compared to theory and simulations.

  8. Continuously tunable delay line based on SOI tapered Bragg gratings.

    PubMed

    Giuntoni, Ivano; Stolarek, David; Kroushkov, Dimitar I; Bruns, Jürgen; Zimmermann, Lars; Tillack, Bernd; Petermann, Klaus

    2012-05-07

    The realization of an integrated delay line using tapered Bragg gratings in a drop-filter configuration is presented. The device is fabricated on silicon-on-insulator (SOI) rib waveguides using a Deep-UV 248 nm lithography. The continuous delay tunability is achieved using the thermo-optical effect, showing experimentally that a tuning range of 450 ps can be obtained with a tuning coefficient of -51 ps/°C. Furthermore the system performance is considered, showing that an operation at a bit rate of 25 Gbit/s can be achieved, and could be extended to 80 Gbit/s with the addition of a proper dispersion compensation.

  9. On-chip optical mode exchange using tapered directional coupler

    PubMed Central

    Zhang, Zhonglai; Hu, Xiao; Wang, Jian

    2015-01-01

    We present an on-chip optical mode exchange between two multiplexed modes by using tapered directional couplers on silicon-on-insulator platform. The device consisting of mode multiplexing and mode exchange is compact with relatively large fabrication error tolerance. The simulation results show efficient higher order mode excitation and mode exchange. A low excess loss less than 0.5 dB and high extinction ratio larger than 15 dB over 10 nm wavelength range from 1535 to 1545 nm are achieved. PMID:26530728

  10. Method of making tapered capillary tips with constant inner diameters

    SciTech Connect

    Kelly, Ryan T.; Page, Jason S.; Tang, Keqi; Smith, Richard D.

    2009-02-17

    Methods of forming electrospray ionization emitter tips are disclosed herein. In one embodiment, an end portion of a capillary tube can be immersed into an etchant, wherein the etchant forms a concave meniscus on the outer surface of the capillary. Variable etching rates in the meniscus can cause an external taper to form. While etching the outer surface of the capillary wall, a fluid can be flowed through the interior of the capillary tube. Etching continues until the immersed portion of the capillary tube is completely etched away.

  11. X-Ray Propagation in Tapered Planar Waveguide

    NASA Astrophysics Data System (ADS)

    Dolocan, Andrei; van der Veen, J. Friso

    The present paper focuses on the tapered planar waveguide solution for an initial given wave form. The algorithm is constructed in distributions space such that the calculations can be actually computed by taking some hypothesis regarding the mode series which appear. The whole argument leads to the conclusion that the wave is compressed towards the waveguide in the direction of tilting, leading thereafter to a focusing phenomena. We present two alternative constructions in order to compute the convolution which gives the wave inside the waveguide. The hypothesis are providing results in good approximation with the real evolution of the field within the definition domain.

  12. Frequency characteristics of tapered backfire helical antenna with loaded termination

    NASA Astrophysics Data System (ADS)

    Nakano, H.; Iio, S.; Yamauchi, J.

    1984-06-01

    Effects of loaded termination on a tapered backfire bifilar helical antenna are numerically and experimentally investigated over a wide frequency range of ratio 1:1.7. With the help of the scalar potential for a lumped resistance at the arm end, the current distribution along the helical wire is determined. It is found that nearly constant input impedance, high front-to-back ratio and low axial ratio are realised. The inherent absolute gain is not significantly deteriorated in spite of the use of a terminal resistor. The existence of the phase centre is also demonstrated, and the phase centre location is presented as a function of frequency.

  13. High-spectral-radiance, red-emitting tapered diode lasers with monolithically integrated distributed Bragg reflector surface gratings.

    PubMed

    Feise, David; John, Wilfred; Bugge, Frank; Fiebig, Christian; Blume, Gunnar; Paschke, Katrin

    2012-10-08

    A red-emitting tapered diode laser with a monolithically integrated distributed Bragg reflector grating is presented. The device is able to emit up to 1 W of spectrally stabilized optical output power at 5°C. Depending on the period of the tenth order surface grating the emission wavelengths of these devices from the same gain material are 635 nm, 637 nm, and 639 nm. The emission is as narrow as 9 pm (FWHM) at 637.6 nm. The lateral beam quality is M(2)(1/e(2)) = 1.2. Therefore, these devices simplify techniques such as wavelength multiplexing and fiber coupling dedicating them as light sources for µ-Raman spectroscopy, absolute distance interferometry, and holographic imaging.

  14. Experiment study of an electron cyclotron resonant ion source based on a tapered resonance cavity

    SciTech Connect

    Yang, Juan; Shi, Feng; Jin, Yizhou; Wang, Yunmin; Komurasaki, Kimiya

    2013-12-15

    Electron cyclotron resonant plasma is one type of magnetised plasma generated by continuous microwave energy. It has the property of high degree of ionization and large volume at low gas pressure, which makes it useful for space propulsion and material processing. This article presents the experiment study of the plasma properties and ion beam extraction from an electron cyclotron resonant ion source based on a tapered resonance cavity. Optical emission spectroscopy based on a simple collisional radiation model was used for plasma diagnosis. Experiment results show that, at microwave power setting ranging from 7.06 to 17.40 W and mass flow rate ranging from 1 to 10 sccm, argon gas can be ionized. Ion beam of 109.1 mA from the ion source can be extracted at microwave power of 30 W, mass flow rate of 10 sccm, and accel voltage of 800 V. The diagnosed plasma temperature and density are 2.4–5.2 eV and 2 × 10{sup 16}–4.8 × 10{sup 17} m{sup −3}, respectively.

  15. Application of keV and MeV ion microbeams through tapered glass capillaries

    NASA Astrophysics Data System (ADS)

    Ikeda, T.; Kojima, T. M.; Kobayashi, T.; Meissl, W.; Mäckel, V.; Kanai, Y.; Yamazaki, Y.

    2012-11-01

    We have developed a method to produce micrometer-sized beams of keV energy highly charged ions (HCIs) and MeV energy protons/helium ions with tapered glass capillary optics for the applications of micrometer sized surface modifications and a biological tool, respectively. The transmission experiments of keV HCIs through the glass capillaries show a density enhancement of about 10, beam guiding up to 5°, and the extracted beam keeping the initial charge-state. The combination of MeV ion beams and the capillary with a thin end window at its outlet was used for the irradiation of a part of nucleus of a HeLa cell in culture solution. Escherichia coli cells are irradiated by MeV proton microbeam to determine the minimum dose to stop the single flagellar motor. Scanning irradiation of polymer surface by the beam extracted from the capillary in solution containing acrylic acid was found to provide a deposition layer with large affinity with water.

  16. Spiralling tapered slip-on drill string stabilizer

    SciTech Connect

    Beasley, T.R.; Teng, C.C.

    1986-12-23

    A stabilizer is described for use in a drilling string comprising: a substantially cylindrical body member having a central passageway to accommodate the drill sting, the inside surface of the body member defining a right-hand spiralling thread with a tapered trailing edge which spirals from a starting point on the body member. The thread terminates internally of the body member in an arcuate recess extending around the interior of the body member; a key member is secured to the inner wall surface of the recess of the body member, the key member having a lug extending longitudinally of the body member within the recess; a slip member adapted to thread within the body member between the body member and the drill string. The slip defines a right-hand thread with a matching tapered trailing edge configured to make up with the right-hand thread on the body member and to wedge between the body member and the drill string. One end of the slip terminates in a longitudinally disposed shoulder capable of abutting the lug upon threading of the clip within the body member.

  17. Moment method analysis of linearly tapered slot antennas

    NASA Technical Reports Server (NTRS)

    Koeksal, Adnan

    1993-01-01

    A method of moments (MOM) model for the analysis of the Linearly Tapered Slot Antenna (LTSA) is developed and implemented. The model employs an unequal size rectangular sectioning for conducting parts of the antenna. Piecewise sinusoidal basis functions are used for the expansion of conductor current. The effect of the dielectric is incorporated in the model by using equivalent volume polarization current density and solving the equivalent problem in free-space. The feed section of the antenna including the microstripline is handled rigorously in the MOM model by including slotline short circuit and microstripline currents among the unknowns. Comparison with measurements is made to demonstrate the validity of the model for both the air case and the dielectric case. Validity of the model is also verified by extending the model to handle the analysis of the skew-plate antenna and comparing the results to those of a skew-segmentation modeling results of the same structure and to available data in the literature. Variation of the radiation pattern for the air LTSA with length, height, and taper angle is investigated, and the results are tabulated. Numerical results for the effect of the dielectric thickness and permittivity are presented.

  18. Fatigue Life Methodology for Tapered Hybrid Composite Flexbeams

    NASA Technical Reports Server (NTRS)

    urri, Gretchen B.; Schaff, Jeffery R.

    2006-01-01

    Nonlinear-tapered flexbeam specimens from a full-size composite helicopter rotor hub flexbeam were tested under combined constant axial tension and cyclic bending loads. Two different graphite/glass hybrid configurations tested under cyclic loading failed by delamination in the tapered region. A 2-D finite element model was developed which closely approximated the flexbeam geometry, boundary conditions, and loading. The analysis results from two geometrically nonlinear finite element codes, ANSYS and ABAQUS, are presented and compared. Strain energy release rates (G) associated with simulated delamination growth in the flexbeams are presented from both codes. These results compare well with each other and suggest that the initial delamination growth from the tip of the ply-drop toward the thick region of the flexbeam is strongly mode II. The peak calculated G values were used with material characterization data to calculate fatigue life curves for comparison with test data. A curve relating maximum surface strain to number of loading cycles at delamination onset compared well with the test results.

  19. Improved oil-off survivability of tapered roller bearings

    NASA Technical Reports Server (NTRS)

    Kreider, Gary E.; Lee, Peter W.

    1987-01-01

    The aim of this program is to improve the oil-off survivability of a tapered roller bearing when applied to a helicopter transmission, since the tapered bearing has shown a performance advantage in this application. However, the critical roller end-rib conjunction is vulnerable to damage in an oil-off condition. Three powdered metal materials were selected to use as the rib material for oil-off evaluation. These were: M2 steel to a 65% density, CBS 1000M 65% density, and CBS 1000M 75% density. The bearing styles tested were ribbed cone (inner race) and ribbed cup (outer race). Carburized solid CBS 600 was also used as a ribbed material for comparison of oil-off results. The tests were conducted at six speeds from 4000 rpm (0.26 million DN) through 37000 rpm (2.4 million DN).The ribbed cup style bearing achieved longer lives than the ribbed cone style. A standard bearing lasted only 10 minutes at 4000 rpm; however, the 30-min oil-off goal was achieved through 11000 rpm using the survivable ribbed cup bearing. The oil-off lives at 37000 rpm were less than 10 seconds. The grinding of the powder metal materials and surface preparation to achieve an open porosity is extremely critical to the oil-off performance of the powder metal component.

  20. Fatigue Life Analysis of Tapered Hybrid Composite Flexbeams

    NASA Technical Reports Server (NTRS)

    Murri, Gretchen B.; Schaff, Jeffery R.; Dobyns, Alan L.

    2002-01-01

    Nonlinear-tapered flexbeam laminates from a full-size composite helicopter rotor hub flexbeam were tested under combined constant axial tension and cyclic bending loads. The two different graphite/glass hybrid configurations tested under cyclic loading failed by delamination in the tapered region. A 2-D finite element model was developed which closely approximated the flexbeam geometry, boundary conditions, and loading. The analysis results from two geometrically nonlinear finite element codes, ANSYS and ABAQUS, are presented and compared. Strain energy release rates (G) obtained from the above codes using the virtual crack closure technique (VCCT) at a resin crack location in the flexbeams are presented for both hybrid material types. These results compare well with each other and suggest that the initial delamination growth from the resin crack toward the thick region of the flexbeam is strongly mode II. The peak calculated G values were used with material characterization data to calculate fatigue life curves and compared with test data. A curve relating maximum surface strain to number of loading cycles at delamination onset compared reasonably well with the test results.

  1. Development of zirconia nanoparticles-decorated calcium alginate hydrogel fibers for extraction of organophosphorous pesticides from water and juice samples: Facile synthesis and application with elimination of matrix effects.

    PubMed

    Zare, Maryam; Ramezani, Zahra; Rahbar, Nadereh

    2016-11-18

    In this research, novel zirconia nanoparticles-decorated calcium alginate hydrogel fibers (ZNCAHF) were synthesized through a simple, green procedure. ZNCAHF were used as an adsorbent in the micro-solid-phase extraction (MSPE) of methyl parathion (MP), fenitrothion (FT) and malathion (MT) as model pesticides prior to gas chromatography-mass spectroscopic detection (GC-MS). The composition and morphology of the prepared fiber were characterized by Fourier transform-infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray diffraction (EDX), and differential scanning calorimetry (DSC). Various parameters affecting fabrication of the fiber (weight ratio of components) and relative extraction recovery (pH, amount of adsorbent, extraction time, salt addition, and desorption conditions) were investigated and optimized. Under optimized conditions, the calibration curves were obtained in the concentration range of 0.01-500ngmL(-1) with regression coefficients between 0.9997 and 0.9999. The limits of detection (LOD) (S/N=3) and limits of quantification (LOQ) (S/N=10) of the method ranged from 0.001 to 0.004ngmL(-1) and 0.003 to 0.012ngmL(-1), respectively. The intra-day and inter-day relative standard deviations (RSDs) were 2.2-5.9% and 3.2-7.8%, respectively. The applicability of the fabricated adsorbent was investigated by extraction of selected organophosphorous pesticides (OPPs) from real samples of juice and water. The obtained relative recoveries were in the range of 90.6-105.4%, demonstrating elimination of matrix effects which can be attributed to the remarkable affinity of OPPs toward ZNCAHF.

  2. Drawing optical fibers from three-dimensional printers.

    PubMed

    Canning, John; Hossain, Md Arafat; Han, Chunyang; Chartier, Loic; Cook, Kevin; Athanaze, Tristan

    2016-12-01

    The temperature distribution within extrusion nozzles of three low-cost desktop 3D printers is characterized using fiber Bragg gratings (FBGs) to assess their compatibility as micro-furnaces for optical fiber and taper production. These profiles show remarkably consistent distributions suitable for direct drawing of optical fiber. As proof of principle, coreless optical fibers (φ=30  μm) made from fluorinated acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate glycol (PETG) are drawn. Cutback measurements demonstrate propagation losses as low as α=0.26  dB/cm, which are comparable with standard optical fiber losses with some room for improvement. This work points toward direct optical fiber manufacture of any material from 3D printers.

  3. Demonstration of a cylindrically symmetric second-order nonlinear fiber with self-assembled organic surface layers.

    PubMed

    Daengngam, Chalongrat; Hofmann, Matthias; Liu, Zhiwen; Wang, Anbo; Heflin, James R; Xu, Yong

    2011-05-23

    We report the fabrication and characterization of a cylindrically symmetric fiber structure that possesses significant and thermodynamically stable second-order nonlinearity. Such fiber structure is produced through nanoscale self-assembly of nonlinear molecules on a silica fiber taper and possesses full rotational symmetry. Despite its highly symmetric configuration, we observed significant second harmonic generation (SHG) and obtained good agreement between experimental results and theoretical predictions.

  4. 77 FR 12326 - Tapered Roller Bearings From China; Scheduling of a Full Five-Year Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-29

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Tapered Roller Bearings From China; Scheduling of a Full Five- Year Review AGENCY: United States... Act) to determine whether revocation of the antidumping duty order on tapered roller bearings...

  5. 77 FR 16859 - Tapered Roller Bearings From China; Scheduling of a Full Five-Year Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Tapered Roller Bearings From China; Scheduling of a Full Five- Year Review AGENCY: United States...)) (the Act) to determine whether revocation of the antidumping duty order on tapered roller bearings...

  6. The mean aerodynamic chord and the aerodynamic center of a tapered wing

    NASA Technical Reports Server (NTRS)

    Diehl, Walter S

    1942-01-01

    A preliminary study of pitching-moment data on tapered wings indicated that excellent agreement with test data was obtained by locating the quarter-chord point of the average chord on the average quarter-chord point of the semispan. The study was therefore extended to include most of the available data on tapered-wing models tested by the NACA.

  7. Simple Expressions for the Design of Linear Tapers in Overmoded Corrugated Waveguides

    DOE PAGES

    Schaub, S. C.; Shapiro, M. A.; Temkin, R. J.

    2015-08-16

    In this paper, simple analytical formulae are presented for the design of linear tapers with very low mode conversion loss in overmoded corrugated waveguides. For tapers from waveguide radius a2 to a1, with a11a2/λ. Here, λ is the wavelength of radiation. The fractional loss of the HE 11 mode in an optimized taper is 0.0293(a2-a1)4/amore » $$2\\atop{1}$$1a$$2\\atop{2}$$. These formulae are accurate when a2≲2a1. Slightly more complex formulae, accurate for a2≤4a1, are also presented in this paper. The loss in an overmoded corrugated linear taper is less than 1 % when a2≤2.12a1 and less than 0.1 % when a2≤1.53a1. The present analytic results have been benchmarked against a rigorous mode matching code and have been found to be very accurate. The results for linear tapers are compared with the analogous expressions for parabolic tapers. Finally, parabolic tapers may provide lower loss, but linear tapers with moderate values of a2/a1 may be attractive because of their simplicity of fabrication.« less

  8. Autotract: automatic cleaning and tracking of fibers

    NASA Astrophysics Data System (ADS)

    Prieto, Juan C.; Yang, Jean Y.; Budin, François; Styner, Martin

    2016-03-01

    We propose a new tool named Autotract to automate fiber tracking in diffusion tensor imaging (DTI). Autotract uses prior knowledge from a source DTI and a set of corresponding fiber bundles to extract new fibers for a target DTI. Autotract starts by aligning both DTIs and uses the source fibers as seed points to initialize a tractography algorithm. We enforce similarity between the propagated source fibers and automatically traced fibers by computing metrics such as fiber length and fiber distance between the bundles. By analyzing these metrics, individual fiber tracts can be pruned. As a result, we show that both bundles have similar characteristics. Additionally, we compare the automatically traced fibers against bundles previously generated and validated in the target DTI by an expert. This work is motivated by medical applications in which known bundles of fiber tracts in the human brain need to be analyzed for multiple datasets.

  9. Autotract: Automatic cleaning and tracking of fibers

    PubMed Central

    Prieto, Juan C.; Yang, Jean Y.; Budin, François; Styner, Martin

    2016-01-01

    We propose a new tool named Autotract to automate fiber tracking in diffusion tensor imaging (DTI). Autotract uses prior knowledge from a source DTI and a set of corresponding fiber bundles to extract new fibers for a target DTI. Autotract starts by aligning both DTIs and uses the source fibers as seed points to initialize a tractography algorithm. We enforce similarity between the propagated source fibers and automatically traced fibers by computing metrics such as fiber length and fiber distance between the bundles. By analyzing these metrics, individual fiber tracts can be pruned. As a result, we show that both bundles have similar characteristics. Additionally, we compare the automatically traced fibers against bundles previously generated and validated in the target DTI by an expert. This work is motivated by medical applications in which known bundles of fiber tracts in the human brain need to be analyzed for multiple datasets. PMID:27065227

  10. Supercontinuum generation in non-silica fibers

    NASA Astrophysics Data System (ADS)

    Price, Jonathan H. V.; Feng, Xian; Heidt, Alexander M.; Brambilla, Gilberto; Horak, Peter; Poletti, Francesco; Ponzo, Giorgio; Petropoulos, Periklis; Petrovich, Marco; Shi, Jindan; Ibsen, Morten; Loh, Wei H.; Rutt, Harvey N.; Richardson, David J.

    2012-09-01

    The development of super continuum sources is driven by the requirements of a wide range of emerging applications. This paper points out how non-silica fibers are of benefit not only because their broad mid-IR transparency enables continuum generation in the 2-5 μm region but also since the high intrinsic nonlinearity of the glasses reduces the power-threshold for devices at wavelengths below 2 μm. For these glasses, the material zero-dispersion wavelength is typically shifted to long wavelengths compared to silica so dispersion tailoring is key to creating sources based on practical, near-IR, solid state pump lasers. We show how modeling work has produced fiber designs that provide flattened dispersion profiles with high nonlinearity coefficients and zero-dispersion wavelengths in the near-IR. Building on this flexibility, modeling of the pulse dynamics then demonstrates how coherent mid-IR supercontinuum sources could be developed. We also show the importance of the second zero-dispersion wavelength using bismuth fibers as an example. Nonlinear mode-coupling is shown to be a factor in larger core fibers for high-power applications. Demonstrations of supercontinuum in microstructured tellurite fibers, all-solid lead-silicate (SF57) fibers and in bismuth fibers and tapers are then reported to show what has been achieved experimentally using a range of materials and fiber geometries.

  11. A Report of Successful Procedural, Clinical, and Angiographic Outcomes with a Tapered Stent of a Patient in Naturally Tapered Coronary Vessel

    PubMed Central

    Kumar, Yerra Shiv

    2017-01-01

    In cases involving stenosis or occlusions in major parts of a long vessel, natural tapering of coronary vessels may create dilemma in deciding the optimal stent size during percutaneous coronary intervention. In this regard, tapered stents have been developed recently. Herein, we present a case of 67-year-old male patient with triple vessel disease including two tandem lesions in naturally tapered Left Anterior Descending (LAD) artery. The patient received a 3.0–2.5x60 mm Sirolimus-eluting BioMime Morph stent (Meril life Sciences, Gujarat, India) in the mid-distal LAD lesion along with conventional stent implantations in other two lesions. The procedure was successful and good coronary flow was obtained after revascularization. The patient remained asymptomatic thereafter. At one year, angiographic follow-up revealed good flow and no restenosis in the LAD vessel. We are of opinion that using tapered stents with decremented diameter may offer the advantages of excellent adaptation to vessel size, vessel tapering, and good apposition in patients with long coronary lesions in tapered vessels. PMID:28273994

  12. Comparison of debris extruded apically and working time used by ProTaper Universal rotary and ProTaper retreatment system during gutta-percha removal

    PubMed Central

    UEZU, Mary Kinue Nakamune; BRITTO, Maria Leticia Borges; NABESHIMA, Cleber K.; PALLOTTA, Raul Capp

    2010-01-01

    Objective The aim of this study was to evaluate the in vitro action of ProTaper retreatment files and ProTaper Universal in the retreatment of mandibular premolars. Material and methods The amount of debris extruded apically was measured and the time to reach the working length and to complete the removal of gutta-percha was observed. Thirty teeth had their canals prepared using ProTaper Universal files and were obturated by the single cone technique. The teeth were then stored at 37ºC in a humid environment for 7 days. During the use of the rotary instruments for root canal filling removal, the apical portions of the teeth were attached to the open end of a resin tube to collect the apically extruded debris. Results ProTaper Universal files were significantly faster (p=0.0011) than the ProTaper retreatment files to perform gutta-percha removal, but no significant difference was found between the files regarding the time to reach the working length or the amount of apical extrusion. Conclusions ProTaper Universal rotary had better results for endodontic retreatment, and both techniques promote similar apical extrusion of debris. PMID:21308282

  13. Comparison of canal transportation in simulated curved canals prepared with ProTaper Universal and ProTaper Gold systems

    PubMed Central

    Muniz, Brenda Leite; Pires, Frederico; Belladonna, Felipe Gonçalves; Neves, Aline Almeida; Souza, Erick Miranda; De-Deus, Gustavo

    2016-01-01

    Objectives The purpose of this study was to assess the ability of ProTaper Gold (PTG, Dentsply Maillefer) in maintaining the original profile of root canal anatomy. For that, ProTaper Universal (PTU, Dentsply Maillefer) was used as reference techniques for comparison. Materials and Methods Twenty simulated curved canals manufactured in clear resin blocks were randomly assigned to 2 groups (n = 10) according to the system used for canal instrumentation: PTU and PTG groups, upto F2 files (25/0.08). Color stereomicroscopic images from each block were taken exactly at the same position before and after instrumentation. All image processing and data analysis were performed with an open source program (FIJI). Evaluation of canal transportation was obtained for two independent canal regions: straight and curved levels. Student's t test was used with a cut-off for significance set at α = 5%. Results Instrumentation systems significantly influenced canal transportation (p < 0.0001). A significant interaction between instrumentation system and root canal level (p < 0.0001) was found. PTU and PTG systems produced similar canal transportation at the straight part, while PTG system resulted in lower canal transportation than PTU system at the curved part. Canal transportation was higher at the curved canal portion (p < 0.0001). Conclusions PTG system produced overall less canal transportation in the curved portion when compared to PTU system. PMID:26877984

  14. Depression of Ca2+ insensitive tension due to reduced pH in partially troponin-extracted skinned skeletal muscle fibers.

    PubMed Central

    Metzger, J M; Moss, R L

    1988-01-01

    Previous studies on skinned muscle fibers have demonstrated a direct effect of elevated levels of H+ ion to depress force production; however, the molecular basis for this effect is presently unknown. Here, whole troponin complexes were removed from skinned single fiber preparations of rat slow-twitch and fast-twitch muscles, and the effect of H+ ions on the resultant Ca2+-insensitive force was examined. The effect of H+ ions to depress force was found to be virtually identical in untreated control fibers activated in the presence of Ca2+ and in fibers activated in the absence of Ca2+ by troponin removal. Thus, the effect of H+ ions to depress force occurs at a step in activation beyond the disinhibition of the thin filament by Ca2+, probably involving reductions in the number of attached cross-bridges or in the force per attachment. PMID:3233271

  15. Two-phase hollow fiber liquid phase microextraction based on magnetofluid for simultaneous determination of Echinacoside, Tubuloside B, Acteoside and Isoacteoside in rat plasma after oral administration of Cistanche salsa extract by high performance liquid chromatography.

    PubMed

    Zhou, Jun; Zhang, Qiong; Sun, Jiang Bing; Sun, Xiao Li; Zeng, Ping

    2014-06-01

    A new and fast sample preparation technique based on two-phase hollow fiber liquid phase microextraction (HF-LPME) with magnetofluid was developed to quantitate and determine the four phenylethanoid glycosides (PhGs) (Echinacoside, Tubuloside B, Acteoside and Isoacteoside) in plasma after oral administration of Cistanche salsa extract. Analysis was accomplished by reversed-phase high performance liquid chromatography (RP-HPLC) with ultraviolet detection. Parameters that affect the HF-LPME processes, such as the content of magnetic powder, the solvent type, salt content, stirring speed, extraction time and hollow fiber length, were investigated and optimized. Under the optimized conditions, the preconcentration factors for PhGs were higher than 625. The calibration curve for PhGs was linear in the range of 0.1-100ngmL(-1) with correlation coefficients greater than 0.9996. The intra-day and inter-day precision (RSD) were below 8.74% and the limits of detection (LOD) for the four PhGs were 8-15pgmL(-1) (S/N=3). The validated method was successfully applied to separate and determine the four PhGs in rat plasma after oral administration of C. salsa extract.

  16. High Efficiency Electron-Laser Interactions in Tapered Helical Undulators

    NASA Astrophysics Data System (ADS)

    Duris, Joseph Patrick

    Efficient coupling of relativistic electron beams with high power radiation lies at the heart of advanced accelerator and light source research and development. The inverse free electron laser is a stable accelerator capable of harnessing very high intensity laser electric fields to efficiently transfer large powers from lasers to electron beams. In this dissertation, we first present the theoretical framework to describe the interaction, and then apply our improved understanding of the IFEL to the design and numerical study of meter-long, GeV IFELs for compact light sources. The central experimental work of the dissertation is the UCLA BNL helical inverse free electron laser experiment at the Accelerator Test Facility in Brookhaven National Laboratory which used a strongly tapered 54cm long, helical, permanent magnet undulator and a several hundred GW CO2 laser to accelerate electrons from 52 to 106MeV, setting new records for inverse free electron laser energy gain (54MeV) and average accelerating gradient (100MeV/m). The undulator design and fabrication as well as experimental diagnostics are presented. In order to improve the stability and quality of the accelerated electron beam, we redesigned the undulator for a slightly reduced output energy by modifying the magnet gap throughout the undulator, and we used this modified undulator to demonstrated capture of >25% of the injected beam without prebunching. In the study of heavily loaded GeV inverse free electron lasers, we show that a majority of the power may be transferred from a laser to the accelerated electron beam. Reversing the process to decelerate high power electron beams, a mechanism we refer to as tapering enhanced stimulated superradiant amplification, offers a clear path to high power light sources. We present studies of radiation production for a wide range of wavelengths (10mum, 13nm, and 0.3nm) using this method and discuss the design for a deceleration experiment using the same undulator used

  17. 76 FR 6397 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished From the People's Republic of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-04

    ... International Trade Administration Tapered Roller Bearings and Parts Thereof, Finished and Unfinished From the... shipper review (``NSR'') of the antidumping duty order on tapered roller bearings (``TRBs'') from the... Order; Tapered Roller Bearings and Parts Thereof, Finished or Unfinished, From the People's Republic...

  18. 76 FR 45777 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished From the People's Republic of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-01

    ... International Trade Administration Tapered Roller Bearings and Parts Thereof, Finished and Unfinished From the... review (``NSR'') of the antidumping duty order on tapered roller bearings (``TRBs'') from the People's... Order; Tapered Roller Bearings and Parts Thereof, Finished or Unfinished, From the People's Republic...

  19. 76 FR 3086 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-19

    ... International Trade Administration Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the... administrative review of tapered roller bearings (``TRBs'') from the People's Republic of China (``PRC''). See Tapered Roller Bearings and Parts Thereof, Finished or Unfinished, From the People's Republic of...

  20. 77 FR 52682 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-30

    ... International Trade Administration Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the... the antidumping duty order on tapered roller bearings and parts thereof, finished and unfinished... should the order be revoked.\\2\\ \\2\\ See Tapered Roller Bearings and Parts Thereof, Finished...